# Nonvitamin, Nonmineral Dietary Supplement Use among Adults with Fibromyalgia: United States, 2007–2012

Authors: Termeh Feinberg; Christa Lilly; Kim Innes
Journal: Evidence-Based Complementary and Alternative Medicine
 (2017)

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## Abstract

Background. Fibromyalgia (FMS) is a pain condition affecting 2–6% of US adults; effective treatment remains limited. Determinants of nonvitamin, nonmineral dietary supplement (NVNM) use among adults with FMS are not well-studied. We investigated the relation of NVNM use to FMS, and trends, in two nationally representative samples of US adults ≥18 years.Methods. Data were drawn from 2007 and 2012 National Health Interview Surveys (N’s = 20127 and 30672, resp.). Logistic regression was used to examine associations of FMS to NVNM use (past 12 months) and evaluate potential modifying influences of gender and comorbidities. Multivariate models adjusted for sampling design, demographic, lifestyle, and health-related factors.Results. FMS was significantly higher in 2012 than in 2007 (1.7% versus 1.3%), whereas NVNM use decreased (57% versus 41%; p<0.0001). Adults reporting diagnosis were more likely to use NVNMs within 12 months, 30 days, or ever relative to adults without; positive associations remained significant after controlling for demographics, lifestyle characteristics, medical history, and other confounders (ranges: 2007 and 2012 AORs = 2.3–2.7; 1.5–1.6, resp.; p’s < 0.0001).Conclusion. In this cross-sectional study of two national samples, NVNM use was strongly and positively associated with FMS, highlighting the need for further study.


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## Body

## 1. Introduction

Fibromyalgia syndrome (FMS) is a rheumatologic neuropathic chronic pain syndrome affecting approximately 2.7% of populations of all ages across the world [1], including an estimated 1.8–6.4% of those in the US [2, 3]. FMS is characterized by a constellation of somatic symptoms (e.g., fatigue, sleep, mood disturbances, and cognitive impairment) that are typically present in addition to widespread pain [4]; the etiology of FMS is largely unknown [4]. Additionally, those with FMS may also experience high rates of comorbidity, such as osteoarthritis [5], autoimmune [6], kidney [7], respiratory [7], and cardiovascular [7, 8] disease, gastrointestinal conditions [7, 9], and headache [1, 7, 10]. Although FMS affects both sexes and people of all ages, the majority of US cases occur in Caucasian, middle-aged women [11, 12].The chronic widespread pain characterizing FMS is difficult to manage, and many physicians remain unfamiliar with FMS diagnostic criteria and treatment [13] often making it difficult for patients to obtain an accurate FMS diagnosis and appropriate care. Although a lack of efficacy evidence for opioids as FMS treatment exists [14, 15] and opioid overdose deaths have more than tripled since 1999 [16, 17], FMS patients may receive opioid therapy [18]. Common treatments for FMS include antidepressants, anticonvulsants, muscle relaxants, and other pain medications [19]. Nonsteroidal anti-inflammatory drugs, which may carry side effects for as many as 25% of long-term users [20], are not currently recommended for FMS by any guidelines [19]. Although three drugs are FDA-approved for FMS treatment [21], these medications may carry significant side effects for some [22] and are not always effective for all [19]. Thus, patients may turn to complementary health approaches (CHAs, defined as medical/healthcare systems or practices used outside of mainstream medicine [23]) to manage symptoms [24]; back, neck, and joint pain are among the most commonly reported conditions for which patients use CHAs in the US [25, 26].Nonvitamin, nonmineral dietary supplements (NVNMs) are a type of CHA used by nearly twenty-five percent of US adults with a musculoskeletal disorder [25] and include animal- and plant-derived products (i.e., fish oil, herbal dietary supplements). The extent and efficacy of NVNMs, particularly herbal dietary supplements, are largely unknown [27, 28]. Although a handful of large surveys have documented high rates of herbal and other NVNM use for chronic pain syndromes [24, 25, 29, 30], and anecdotal accounts indicate that a wide range of herbs have been used for the treatment of FMS [31], rigorous investigations regarding the prevalence and correlates of NVNM use in FMS remain limited. To address these gaps, we assessed the relation of FMS to NVNM use in two large, representative samples of US adults and examined potential changes in prevalence rates for NVNM use among those with FMS over a 5-year time period.


## 2. Materials and Methods

### 2.1. Data Sources

Participants for this study were drawn from two nationally representative samples of 23,501 and 34,525 US adults (National Health Interview Surveys (NHIS), 2007 and 2012, resp.). The NHIS is an annual national, cross-sectional household survey of the noninstitutionalized US population and is administered by the Centers for Disease Control and Prevention’s National Center for Health Statistics. A supplement (adult alternative medicine) to the core individual, family, and household surveys asked participants about use of a broad range of CHAs, including herbs and other NVNMs, for both years. All questions were administered in a personal interview format. Adult response rates to the NHIS were 78.3% in 2007 and 79.7% in 2012, respectively [32].The NHIS is the only national, public-use survey that includes comprehensive sets of questions regarding NVNM and other CHA use. Both 2007 and 2012 surveys used a stratified multistage probability design weighted on age, sex, and race/ethnicity, using 2000 and 2010 Census data for each, respectively. Both surveys oversampled Asian, Black, Hispanic, and minority elderly populations. Thus, each person in the covered population had a known nonzero probability of selection. Additional project details have been described elsewhere [32].


### 2.2. Study Population

Our analysis excluded participants who were <18 years of age, were pregnant, had functional limitation(s) due to senility, had a stroke and used a proxy to complete the interview, or had current cancer; those missing data on key covariates were also excluded, as were participants with extreme values for exercise (>6,000 minutes per week) in order to eliminate potential information bias. Further exclusion of persons with missing data on FMS and NVNM use (at 30 days, at 12 months, or ever using NVNMs) yielded final study samples of 20,127 and 30,672 adults for 2007 and 2012, respectively (Figure1).Figure 1
Study flow diagram for nonvitamin, nonmineral dietary supplement (NVNM) use in two national datasets.


### 2.3. Variables

#### 2.3.1. Outcome Variables

The main outcome variable for this study was the reported use of NVNMs within the past 12 months (Y/N). We additionally assessed use of NVNMs within the previous 30 days (Y/N) and ever (Y/N). Briefly, survey participants were shown a card with a list of NVNMs (for which the majority were comprised of herbs or their compounds; 2007 list: 44 NVNM items with additional queries for up to two combination supplements, and 2012 list: 21 NVNM items with additional queries for up to two combination supplements) and queried for a dichotomous response regarding consumption of any “herbal or other nonvitamin supplements.” NVNMs included those labelled “dietary supplement” and in the form of pills, capsules, tablets, or (2012) liquids (including tinctures) and did not include homeopathic or cannabis products.


#### 2.3.2. Exposure Variable

Our main exposure was fibromyalgia syndrome (FMS) (Y/N), ascertained as an affirmative response to fibromyalgia after being asked “Have you EVER been told by a doctor or other health professional that you had some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia? Which of these were you told you had?”


#### 2.3.3. Covariates

Demographics, lifestyle factors, health conditions, and medical care-related factors known or suspected to be associated with CHAs, NVNM use, and/or FMS were considered a priori as potential covariates in multivariate models. Demographic factors assessed included age, gender, race/ethnicity, education, employment, income, marital status, geographic region, and place of birth. Additional related factors included insurance status, annual family out-of-pocket medical costs, and delay of care due to concerns over cost. Lifestyle factors included smoking status, alcohol use, exercise, BMI (using the National Institutes of Health clinical classifications scores) [33], health status, and substance abuse. Health conditions included self-reported history of physician-diagnosed diabetes, kidney disease, gastrointestinal disorder, respiratory conditions, dyslipidemia, liver condition, rheumatoid arthritis, cardiovascular disease, hypertension, nonspecific arthritis, gout, migraines, mental health condition, insomnia, and previous cancer diagnosis. These variables are described in greater detail below.


### 2.4. Statistical Analysis

We conducted complete-case analyses using SAS 9.4 (Cary, NC, USA) and used sampling weights to account for complex survey procedures; these were adjusted for the probabilities of selection, nonresponse, and poststratification [34]. We merged NHIS family, person, household, sample adult, and adult alternative health files for each year and measured sample characteristics, including frequencies/prevalence rates of NVNM use (previous or current use, past 12 months, and past 30 days) for 2007 and 2012, respectively; we extrapolated estimates to generate population frequencies using NHIS sampling weights. Weighted t-tests and Rao-Scott Chi-square tests were used to determine significant differences by NVNM use status for three outcome time points in both survey years; significant factors were included in models as covariates. We also used a DOMAIN statement to keep our exclusions separate while maintaining the integrity of sampling weights and used Chi-square and t-tests to determine significant changes between 2007 and 2012 on weighted frequencies and means of all items, in addition to number of different NVNMs used, physician disclosure of NVNM use, and use of other CHAs. We considered trends between time points significant if there was no overlap in weighted percentage confidence intervals. Differences between participants with versus without missing data were assessed. All p values shown are two-sided at p≤0.05.Weighted logistic regressions were used to evaluate the independent associations of FMS diagnosis to NVNM use in the last 30 days or 12 months or ever. All multivariate models were adjusted for demographics and medical care-related factors; additional models also included lifestyle characteristics and health conditions.Demographic characteristics included age (evaluated as both a continuous and categorical variable (18–24, 25–44, 45–64, 65–74, and 75+ years)), sex (male/female), race (“non-Hispanic White,” “non-Hispanic Black,” “Hispanic,” “Asian,” and “other”), marital status (“married/cohabitating,” “divorced/separated/widowed,” and “single”), education (“≤some HS,” “HS/GED,” “some college/AA/tech,” and “bachelor’s degree+”), employment (“employed for pay,” “employed but not for pay,” and “unemployed”), income ($1–$24,999; $25,000–$44,999; $45,000–$74,999; $75,000+; “do not know;” and “missing”), geographic region (“northeast,” “midwest,” “south,” and “west”), and place of birth (US-born/other). Medical care-related factors included insurance status (“uninsured,” “Medicaid,” “Medicare,” “disability,” and “private”), annual out-of-pocket medical costs (“none”; <$500; $500–$1999; $2000–$2999; $3000–$4999; $5000 and over; and “do not know”), and delayed access to care because they “could not afford” or “worried about cost” (yes/no). Additional analyses also controlled for lifestyle-related factors, including BMI (evaluated as continuous and categorical (<18.5 = “underweight,” 18.5–25 = “underweight or normal weight,” 25–29.9 = “overweight,” 30–34.9 = “obese class 1,” and 35+ = “obese classes 2/3”)) [35]; tobacco use (“current smoker,” “former smoker,” and “never smoked”); alcohol use (“none,” “light,” and “moderate to heavy”); substance abuse other than tobacco or alcohol in past year (yes/no); and physical activity (continuous, in minutes/week).In our fully adjusted models, we also evaluated the potentially confounding influence of self-reported health status (“excellent/very good/good,” “fair,” and “poor”), specific health conditions, and total number of health conditions; this comorbidity index was created from 0–13 participant-reported conditions, including a history of (1) diabetes; (2) kidney disease; (3) gastrointestinal disorder (including history of ulcers, inflammatory/irritable bowel disease, or constipation severe enough to require medication in the past year and/or (2012) abdominal pain, digestive allergy, and/or heartburn in the past year); (4) respiratory conditions (history of asthma or emphysema and/or chronic bronchitis); (5) dyslipidemia; (6) liver condition; (7) rheumatoid arthritis; (8) cardiovascular disease (coronary heart disease, angina, and/or heart attack); (9) hypertension; (10) nonspecific arthritis; (11) gout; (12) migraines; and (13) mental health condition (depression, phobias, and/or being often anxious in past year and/or ever having bipolar disorder). Health conditions were evaluated both collectively and individually; insomnia in the past year and previous cancer diagnosis were evaluated individually.We also assessed the potential modifying influence of gender and presence of comorbid health conditions (0-1 versus 2+) on the association between FMS and NVNM use at each outcome time point and for each survey year by including the corresponding multiplicative-interaction term in age-adjusted models.


## 2.1. Data Sources

Participants for this study were drawn from two nationally representative samples of 23,501 and 34,525 US adults (National Health Interview Surveys (NHIS), 2007 and 2012, resp.). The NHIS is an annual national, cross-sectional household survey of the noninstitutionalized US population and is administered by the Centers for Disease Control and Prevention’s National Center for Health Statistics. A supplement (adult alternative medicine) to the core individual, family, and household surveys asked participants about use of a broad range of CHAs, including herbs and other NVNMs, for both years. All questions were administered in a personal interview format. Adult response rates to the NHIS were 78.3% in 2007 and 79.7% in 2012, respectively [32].The NHIS is the only national, public-use survey that includes comprehensive sets of questions regarding NVNM and other CHA use. Both 2007 and 2012 surveys used a stratified multistage probability design weighted on age, sex, and race/ethnicity, using 2000 and 2010 Census data for each, respectively. Both surveys oversampled Asian, Black, Hispanic, and minority elderly populations. Thus, each person in the covered population had a known nonzero probability of selection. Additional project details have been described elsewhere [32].


## 2.2. Study Population

Our analysis excluded participants who were <18 years of age, were pregnant, had functional limitation(s) due to senility, had a stroke and used a proxy to complete the interview, or had current cancer; those missing data on key covariates were also excluded, as were participants with extreme values for exercise (>6,000 minutes per week) in order to eliminate potential information bias. Further exclusion of persons with missing data on FMS and NVNM use (at 30 days, at 12 months, or ever using NVNMs) yielded final study samples of 20,127 and 30,672 adults for 2007 and 2012, respectively (Figure1).Figure 1
Study flow diagram for nonvitamin, nonmineral dietary supplement (NVNM) use in two national datasets.


## 2.3. Variables

### 2.3.1. Outcome Variables

The main outcome variable for this study was the reported use of NVNMs within the past 12 months (Y/N). We additionally assessed use of NVNMs within the previous 30 days (Y/N) and ever (Y/N). Briefly, survey participants were shown a card with a list of NVNMs (for which the majority were comprised of herbs or their compounds; 2007 list: 44 NVNM items with additional queries for up to two combination supplements, and 2012 list: 21 NVNM items with additional queries for up to two combination supplements) and queried for a dichotomous response regarding consumption of any “herbal or other nonvitamin supplements.” NVNMs included those labelled “dietary supplement” and in the form of pills, capsules, tablets, or (2012) liquids (including tinctures) and did not include homeopathic or cannabis products.


### 2.3.2. Exposure Variable

Our main exposure was fibromyalgia syndrome (FMS) (Y/N), ascertained as an affirmative response to fibromyalgia after being asked “Have you EVER been told by a doctor or other health professional that you had some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia? Which of these were you told you had?”


### 2.3.3. Covariates

Demographics, lifestyle factors, health conditions, and medical care-related factors known or suspected to be associated with CHAs, NVNM use, and/or FMS were considered a priori as potential covariates in multivariate models. Demographic factors assessed included age, gender, race/ethnicity, education, employment, income, marital status, geographic region, and place of birth. Additional related factors included insurance status, annual family out-of-pocket medical costs, and delay of care due to concerns over cost. Lifestyle factors included smoking status, alcohol use, exercise, BMI (using the National Institutes of Health clinical classifications scores) [33], health status, and substance abuse. Health conditions included self-reported history of physician-diagnosed diabetes, kidney disease, gastrointestinal disorder, respiratory conditions, dyslipidemia, liver condition, rheumatoid arthritis, cardiovascular disease, hypertension, nonspecific arthritis, gout, migraines, mental health condition, insomnia, and previous cancer diagnosis. These variables are described in greater detail below.


## 2.3.1. Outcome Variables

The main outcome variable for this study was the reported use of NVNMs within the past 12 months (Y/N). We additionally assessed use of NVNMs within the previous 30 days (Y/N) and ever (Y/N). Briefly, survey participants were shown a card with a list of NVNMs (for which the majority were comprised of herbs or their compounds; 2007 list: 44 NVNM items with additional queries for up to two combination supplements, and 2012 list: 21 NVNM items with additional queries for up to two combination supplements) and queried for a dichotomous response regarding consumption of any “herbal or other nonvitamin supplements.” NVNMs included those labelled “dietary supplement” and in the form of pills, capsules, tablets, or (2012) liquids (including tinctures) and did not include homeopathic or cannabis products.


## 2.3.2. Exposure Variable

Our main exposure was fibromyalgia syndrome (FMS) (Y/N), ascertained as an affirmative response to fibromyalgia after being asked “Have you EVER been told by a doctor or other health professional that you had some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia? Which of these were you told you had?”


## 2.3.3. Covariates

Demographics, lifestyle factors, health conditions, and medical care-related factors known or suspected to be associated with CHAs, NVNM use, and/or FMS were considered a priori as potential covariates in multivariate models. Demographic factors assessed included age, gender, race/ethnicity, education, employment, income, marital status, geographic region, and place of birth. Additional related factors included insurance status, annual family out-of-pocket medical costs, and delay of care due to concerns over cost. Lifestyle factors included smoking status, alcohol use, exercise, BMI (using the National Institutes of Health clinical classifications scores) [33], health status, and substance abuse. Health conditions included self-reported history of physician-diagnosed diabetes, kidney disease, gastrointestinal disorder, respiratory conditions, dyslipidemia, liver condition, rheumatoid arthritis, cardiovascular disease, hypertension, nonspecific arthritis, gout, migraines, mental health condition, insomnia, and previous cancer diagnosis. These variables are described in greater detail below.


## 2.4. Statistical Analysis

We conducted complete-case analyses using SAS 9.4 (Cary, NC, USA) and used sampling weights to account for complex survey procedures; these were adjusted for the probabilities of selection, nonresponse, and poststratification [34]. We merged NHIS family, person, household, sample adult, and adult alternative health files for each year and measured sample characteristics, including frequencies/prevalence rates of NVNM use (previous or current use, past 12 months, and past 30 days) for 2007 and 2012, respectively; we extrapolated estimates to generate population frequencies using NHIS sampling weights. Weighted t-tests and Rao-Scott Chi-square tests were used to determine significant differences by NVNM use status for three outcome time points in both survey years; significant factors were included in models as covariates. We also used a DOMAIN statement to keep our exclusions separate while maintaining the integrity of sampling weights and used Chi-square and t-tests to determine significant changes between 2007 and 2012 on weighted frequencies and means of all items, in addition to number of different NVNMs used, physician disclosure of NVNM use, and use of other CHAs. We considered trends between time points significant if there was no overlap in weighted percentage confidence intervals. Differences between participants with versus without missing data were assessed. All p values shown are two-sided at p≤0.05.Weighted logistic regressions were used to evaluate the independent associations of FMS diagnosis to NVNM use in the last 30 days or 12 months or ever. All multivariate models were adjusted for demographics and medical care-related factors; additional models also included lifestyle characteristics and health conditions.Demographic characteristics included age (evaluated as both a continuous and categorical variable (18–24, 25–44, 45–64, 65–74, and 75+ years)), sex (male/female), race (“non-Hispanic White,” “non-Hispanic Black,” “Hispanic,” “Asian,” and “other”), marital status (“married/cohabitating,” “divorced/separated/widowed,” and “single”), education (“≤some HS,” “HS/GED,” “some college/AA/tech,” and “bachelor’s degree+”), employment (“employed for pay,” “employed but not for pay,” and “unemployed”), income ($1–$24,999; $25,000–$44,999; $45,000–$74,999; $75,000+; “do not know;” and “missing”), geographic region (“northeast,” “midwest,” “south,” and “west”), and place of birth (US-born/other). Medical care-related factors included insurance status (“uninsured,” “Medicaid,” “Medicare,” “disability,” and “private”), annual out-of-pocket medical costs (“none”; <$500; $500–$1999; $2000–$2999; $3000–$4999; $5000 and over; and “do not know”), and delayed access to care because they “could not afford” or “worried about cost” (yes/no). Additional analyses also controlled for lifestyle-related factors, including BMI (evaluated as continuous and categorical (<18.5 = “underweight,” 18.5–25 = “underweight or normal weight,” 25–29.9 = “overweight,” 30–34.9 = “obese class 1,” and 35+ = “obese classes 2/3”)) [35]; tobacco use (“current smoker,” “former smoker,” and “never smoked”); alcohol use (“none,” “light,” and “moderate to heavy”); substance abuse other than tobacco or alcohol in past year (yes/no); and physical activity (continuous, in minutes/week).In our fully adjusted models, we also evaluated the potentially confounding influence of self-reported health status (“excellent/very good/good,” “fair,” and “poor”), specific health conditions, and total number of health conditions; this comorbidity index was created from 0–13 participant-reported conditions, including a history of (1) diabetes; (2) kidney disease; (3) gastrointestinal disorder (including history of ulcers, inflammatory/irritable bowel disease, or constipation severe enough to require medication in the past year and/or (2012) abdominal pain, digestive allergy, and/or heartburn in the past year); (4) respiratory conditions (history of asthma or emphysema and/or chronic bronchitis); (5) dyslipidemia; (6) liver condition; (7) rheumatoid arthritis; (8) cardiovascular disease (coronary heart disease, angina, and/or heart attack); (9) hypertension; (10) nonspecific arthritis; (11) gout; (12) migraines; and (13) mental health condition (depression, phobias, and/or being often anxious in past year and/or ever having bipolar disorder). Health conditions were evaluated both collectively and individually; insomnia in the past year and previous cancer diagnosis were evaluated individually.We also assessed the potential modifying influence of gender and presence of comorbid health conditions (0-1 versus 2+) on the association between FMS and NVNM use at each outcome time point and for each survey year by including the corresponding multiplicative-interaction term in age-adjusted models.


## 3. Results and Discussion

Relative to participants with complete data in both survey years, those with missing data on key covariates were less likely to be employed and report high educational attainment and more likely to be underweight, be older, and indicate poor reported health status (p’s ≤ 0.0001). Participant age ranged from 18 to 85 years, averaging 47.5±0.25 and 48.5±0.18 years for 2007 and 2012, respectively. In both years, study participants were predominantly white (72.2% and 69.5%, resp.), female (53.1% and 53.5%), and insured (84.3% and 84.2%); most (56.4% and 57.9%) reported they never smoked cigarettes. Excluding prayer, most participants had used at least one CHA before (69.8% and 68.8%), and a majority had also used natural products other than NVNMs (60.4% and 62.4%) (not shown). In both years, 35% were overweight (mean BMI = 27.4±0.05 and 27.7±0.04, for 2007 and 2012, resp.), and most (63% and 72%) reported at least one chronic health condition, with the number of chronic health conditions increasing from a mean of 1.5±0.02 in 2007 to 1.9±0.01 in 2012.Table1 illustrates the distribution of demographic and lifestyle characteristics, stratified by year and NVNM use in the past 12 months; medical-related/health characteristics are displayed in Table 2. The percentage of adults reporting NVNM use (ever) declined significantly between time points (p<0.0001) from 27.1% of the sample population in 2007 (n=5057) to 24.2% in 2012 (n=7238; not shown). In contrast, the percentage of adults reporting use of NVNMs within the last 12 months (19.1% to 18.5%, resp.) and 30 days (13.9% in both years; not shown) remained approximately the same. Prevalence of diagnosed FMS also increased from 1.3% to 1.7% (p<0.0001) (Table 3). Consistent with a slight decrease in overall NVNM use among the general population, overall NVNM use among adults diagnosed with FMS declined from 57% in 2007 to 41% in 2012 (p<0.0001). There were no apparent changes in the number of different combination NVNM supplements taken among those with FMS (mean (SE) for past 30 days = 0.99 (0.20) in 2007, 1.1 (0.38) in 2012, p=0.89).Table 1
Demographic and lifestyle characteristics of 2007 and 2012 national US samples, stratified by NVNM use in the past 12 months, National Health Interview Survey.
Characteristic
2007 (N = 20,127)
p
2012 (N = 30,672)
p
OverallpW
NVNM Use
NVNM Use
Yes
95% CI
Weighted population estimate∗
No
Yes
95% CI
Weighted population estimate∗∗
No
N (%)
N (%)
N (%)
N (%)
Total
3582 (19.1)
(18.4, 19.8)
16270972
16545 (80.9)
5490 (18.5)
(17.8, 19.2)
16713004
25182 (72.4)
<0.0001
Age in years
<0.0001
<0.0001
<0.0001
18–24
269 (8.2)
(6.8, 9.6)
1332833
1884 (11.7)
391 (7.4)
(6.3, 8.4)
1231081
2637 (11.1)
25–44
1169 (31.9)
(30.1, 33.7)
5193487
6195 (36.3)
1775 (32.1)
(30.4, 33.7)
5358304
8879 (34.1)
45–64
1414 (39.8)
(37.9, 41.7)
6476821
5314 (32.3)
2162 (39.1)
(37.5, 40.8)
6542615
8379 (33.1)
65–75
462 (12.6)
(11.4, 13.7)
2044193
1599 (9.5)
741 (14.0)
(12.8, 15.1)
2332396
2777 (11.4)
75+
268 (7.5)
(6.5, 8.5)
1223638
1553 (10.2)
421 (7.5)
(6.6, 8.4)
1248608
2510 (10.3)
Mean (SE)
49.06 (0.35)
(48.38, 49.75)
47.09 (0.27)
<0.0001
49.58 (0.33)
(48.93, 50.23)
48.24 (0.19)
<0.0001
0.2794
Sex
0.0001
<0.0001
<0.0001
Male
1535 (43.2)
(41.3, 45.1)
7028291
7644 (47.8)
2341 (42.8)
(41.1, 44.5)
7153927
11565 (47.3)
Female
2047 (56.8)
(54.9, 58.7)
9242681
8901 (52.2)
3149 (57.2)
(55.5, 58.9)
9559077
13617 (52.7)
Race/ethnicity
<0.0001
<0.0001
<0.0001
Non-Hispanic  White
2716 (82.9)
(81.7, 84.1)
13487880
9419 (69.6)
3979 (78.8)
(77.5, 80.1)
13163299
14637 (67.4)
∗
∗
∗
Non-Hispanic  Black
329 (6.9)
(6.0, 7.8)
1121133
2812 (13.5)
513 (7.6)
(6.7, 8.4)
1266927
4058 (13.3)
Hispanic
360 (6.7)
(5.9, 7.5)
1091895
3358 (12.8)
622 (9.0)
(8.1, 9.8)
1496127
4796 (14.4)
∗
∗
∗
Asian
99 (1.8)
(1.4, 2.2)
297318
547 (2.3)
196 (2.6)
(2.2, 3.0)
438850
975 (2.9)
Other  Race/ethnicity
78 (1.7)
(1.3, 2.0)
272746
409 (1.8)
180 (2.1)
(1.7, 2.4)
347801
716 (2.1)
Marital status
0.088
0.009
<0.0001
Married/ Cohabitating
1903 (52.0)
(50.0, 53.9)
8453944
8507 (51.4)
2865 (52.1)
(50.2, 53.9)
8703339
12354 (49.4)
Never married
710 (21.0)
(19.2, 22.7)
3411156
3800 (23.1)
1206 (22.8)
(21.2, 24.4)
3813588
6184 (24.7)
Divorced/sep/ widow
969 (27.1)
(25.5, 28.7)
4405872
4238 (25.6)
1419 (25.1)
(23.7, 26.5)
4196077
6644 (25.9)
Education
<0.0001
<0.0001
<0.0001
<12th grade
272 (7.0)
(6.1, 7.8)
1131795
3307 (16.5)
417 (6.4)
(5.7, 7.2)
1076502
4420 (15.1)
HS/GED
808 (22.3)
(20.7, 23.8)
3624376
4830 (29.6)
1043 (18.4)
(17.2, 19.6)
3078409
6860 (26.8)
∗
∗
∗
Tech training/ some college
1185 (33.4)
(31.6, 35.2)
5436406
4527 (28.5)
1924 (35.3)
(33.6, 36.9)
5896361
7548 (30.7)
≥Bachelor’s degree
1317 (37.4)
(35.4, 39.3)
6078395
3881 (25.4)
2106 (39.9)
(38.1, 41.6)
6661732
6354 (27.4)
Employment
<0.0001
<0.0001
<0.0001
Employed for pay
2189 (61.6)
(59.8, 63.3)
10016152
9818 (59.5)
3301 (60.2)
(58.5, 61.9)
10065089
13857 (55.4)
Employed but not  for pay
162 (4.8)
(4.0, 5.6)
784425
465 (3.1)
227 (4.3)
(3.7, 5.0)
725979
703 (3.0)
Unemployed
1231 (33.6)
(31.9, 35.3)
5470395
6262 (37.4)
1962 (35.4)
(33.7, 37.1)
5921936
10622 (41.7)
Income
<0.0001
<0.0001
<0.0001
$1–$24,999
820 (23.4)
(21.8, 25.1)
3809168
3710 (22.2)
1186 (21.0)
(19.8, 22.3)
3512363
5670 (21.6)
$25,000–$44,999
576 (15.7)
(14.3, 17.1)
2553714
2545 (15.9)
894 (16.3)
(15.1, 17.5)
2727946
3675 (14.5)
$45,000–$74,999
478 (13.5)
(12.2, 14.9)
2203952
1643 (10.6)
803 (14.9)
(13.7, 16.0)
2490180
2727 (11.5)
$75,000 and over
341 (10.0)
(8.8, 11.1)
1622926
858 (5.6)
583 (11.4)
(10.4, 12.5)
1912903
1683 (7.5)
Do not know
129 (3.6)
(3.0, 4.2)
578665
944 (5.3)
189 (3.2)
(2.6, 3.8)
538020
1103 (4.3)
Missing
1238 (33.8)
(31.9, 35.7)
5502547
6845 (40.4)
1835 (33.1)
(31.6, 34.6)
5531592
10324 (40.5)
Geographic location
<0.0001
<0.0001
<0.0001
Northeast
541 (15.5)
(13.8, 17.2)
2526830
2783 (17.4)
762 (13.9)
(12.5, 15.3)
2324064
4325 (18.3)
Midwest
850 (25.6)
(23.1, 28.1)
4161206
3642 (25.0)
1230 (26.2)
(24.2, 28.1)
4374539
5173 (23.3)
South
1190 (32.2)
(29.7, 34.7)
5232720
6337 (37.8)
1506 (29.2)
(26.8, 31.7)
4886374
9683 (38.9)
West
1001 (26.7)
(24.6, 28.9)
4350216
3783 (19.8)
1992 (30.7)
(28.6, 32.7)
5128027
6001 (19.6)
Place of birth
<0.0001
US born
3164 (91.0)
(90.1, 91.9)
14807161
13116 (85.4)
<0.0001
4791 (89.8)
(88.9, 90.7)
15010846
20112 (83.5)
<0.0001
Note. Column percentages shown; ∗adjusted for age, sex, and race/ethnicity based on 2000 Census data; ∗∗adjusted for age, sex, and race/ethnicity based on 2010 Census data; ∗∗∗significant changes between 2007 and 2012 indicated by nonoverlapping weighted population confidence intervals; pW values obtained by comparing weighted estimates; note: significant changes between datasets with differing weighting schemes indicated by nonoverlapping weighted population confidence intervals as ∗∗∗.Table 2
Medical care/health characteristics of 2007 and 2012 national US samples, stratified by NVNM use in the past 12 months, National Health Interview Survey.
Characteristic
2007 (N = 20,127)
p
2012 (N = 30,672)
p
OverallpW
NVNM use
NVNM Use
Yes
95% CI
Weighted population estimate∗
No
Yes
95% CI
Weighted population estimate∗∗
No
N (%)
N (%)
N (%)
N (%)
Insurance status
Uninsured
505 (13.4)
(12.4, 14.5)
2185136
2999 (16.2)
<0.0001
790 (13.0)
(12.0, 13.9)
2168607
4705 (16.5)
<0.0001
<0.0001
Medicaid
155 (4.0)
(3.3, 4.6)
645744
1510 (7.6)
<0.0001
287 (4.4)
(5.2, 10.5)
735478
2736 (9.3)
<0.0001
<0.0001
∗
∗
∗
Medicare
786 (21.6)
(20.0, 23.2)
3519561
3466 (21.7)
0.623
1277 (23.3)
(21.8, 24.8)
3892141
5922 (23.9)
0.451
<0.0001
Disability
63 (2.0)
(1.3, 2.7)
321398
165 (0.96)
<0.0001
111 (2.1)
(1.7, 2.5)
346117
258 (1.1)
<0.0001
<0.0001
Private  insurance
2537 (72.6)
(70.9, 74.3)
11813273
10211 (65.3)
<0.0001
3736 (70.2)
(68.7, 71.8)
11739270
14238 (60.2)
<0.0001
<0.0001
Out of pocket costs, annual$
<0.0001
<0.0001
<0.0001
None
286 (7.8)
(6.8, 8.8)
1272433
2155 (11.7)
483 (8.1)
(7.3, 9.0)
1358939
3811 (13.9)
<$500
1249 (35.0)
(33.3, 36.8)
5700791
6719 (39.6)
1780 (31.3)
(29.7, 32.9)
5230362
9593 (37.3)
∗
∗
∗
$500–$1999
1236 (34.1)
(32.4, 35.8)
5549126
4755 (29.5)
1809 (33.8)
(32.4, 35.1)
5641914
6938 (28.3)
$2000–$2999
333 (9.3)
(8.3, 10.3)
1512573
1151 (7.7)
554 (10.3)
(9.3, 11.3)
1717635
2025 (8.7)
$3000–$4999
217 (6.2)
(5.3, 7.1)
1008834
691 (4.5)
420 (8.3)
(7.5, 9.1)
1391128
1237 (5.1)
∗
∗
∗
$5000+
222 (6.4)
(5.6, 7.2)
1039327
635 (4.1)
396 (7.3)
(6.5, 8.1)
1219938
1180 (5.1)
Do not know
39 (1.2)
(0.74, 1.6)
187888
439 (2.9)
48 (0.9)
(0.63, 1.2)
153088
398 (1.6)
Delayed care because they could not afford/worried about cost
621 (17.6)
(16.2, 19.0)
2867318
1947 (12.0)
<0.0001
964 (16.7)
(15.6, 17.9)
2794500
3478 (13.2)
<0.0001
<0.0001
Perceived health status
0.001
0.001
<0.0001
Excellent/very  good/good
3133 (87.7)
(86.6, 88.9)
14272846
14162 (86.3)
4849 (89.7)
(88.8, 90.6)
14987051
21383 (86.2)
Fair
363 (10.0)
(9.0, 11.1)
1632026
1781 (10.1)
505 (8.1)
(7.3, 8.9)
1347889
2942 (10.7)
∗
∗
∗
Poor
86 (2.3)
(1.7, 2.8)
366100
602 (3.6)
136 (14.0)
(1.8, 2.7)
378064
857 (86.0)
Physical activityR
None
915 (24.6)
(22.9, 26.3)
4001744
7428 (42.2)
<0.0001
1078 (18.9)
(17.7, 20.1)
3158655
9136 (34.8)
<0.0001
<0.0001
∗
∗
∗
Low/moderate
2298 (65.3)
(63.3, 67.3)
10629710
7504 (47.5)
<0.0001
3837 (70.8)
(69.5, 72.2)
11841154
13429 (54.8)
<0.0001
<0.0001
∗
∗
∗
High
1613 (46.5)
(44.5, 48.5)
7571196
5164 (33.8)
<0.0001
2924 (54.7)
(53.0, 56.3)
9136857
9817 (40.6)
<0.0001
<0.0001
∗
∗
∗
Mean (SE)(weekly) (min)
283.09 (10.23)
(262.96, 303.22)
198.45 (6.00)
<0.0001
325.00 (9.77)
(305.77, 344.24)
239.65 (4.63)
<0.0001
0.003
∗
∗
∗
Body mass index (BMI)
0.016
0.031
<0.0001
<24.9
1384 (39.0)
(37.3, 40.8)
6348273
6243 (38.7)
2057 (38.6)
(37.0, 40.1)
6448785
9039 (36.3)
25–29.9
1246 (34.5)
(32.7, 36.2)
5605830
5875 (35.4)
1916 (34.4)
(32.9, 36.0)
5757553
8717 (34.8)
30–35
614 (17.2)
(15.8, 18.6)
2793014
2731 (16.1)
903 (16.3)
(15.1, 17.4)
2718245
4425 (17.3)
35+
338 (9.4)
(8.3, 10.5)
1523855
1696 (9.9)
614 (10.7)
(9.8, 11.6)
1788421
3001 (11.6)
Mean (SE)
27.37 (0.11)
(27.15, 27.60)
27.35 (0.56)
0.887
27.54 (0.09)
(27.36, 27.72)
27.77 (0.05)
0.024
0.2305
Tobacco use
<0.0001
<0.0001
<0.0001
Never
1894 (51.2)
(49.2, 53.2)
8330263
9977 (57.6)
3114 (56.3)
(54.8, 57.9)
9413789
14939 (58.3)
∗
∗
∗
Former
1067 (30.3)
(28.7, 31.9)
4930987
3292 (21.2)
1539 (28.6)
(27.3, 30.0)
4788193
5281 (22.0)
Current
621 (18.5)
(16.7, 20.3)
3009722
3276 (21.2)
837 (15.0)
(13.8, 16.2)
2511022
4962 (19.6)
∗
∗
∗
Alcohol use
<0.0001
<0.0001
<0.0001
None
1006 (26.7)
(25.1, 28.4)
4349888
6958 (39.0)
1454 (24.0)
(22.5, 25.5)
4012831
9897 (36.6)
Light
1740 (47.9)
(46.1, 49.7)
7794610
6609 (41.0)
2662 (49.6)
(48.0, 51.3)
8292892
10426 (42.7)
Moderate to  heavy
836 (25.4)
(23.6, 27.1)
4126474
2978 (19.9)
1374 (26.4)
(24.9, 27.9)
15263475
4859 (20.7)
Substance abuse
30 (0.81)
(0.52, 1.1)
132414
96 (0.62)
0.157
62 (1.3)
(0.89, 1.6)
210988
164 (0.66)
0.0003
<0.0001
Comorbidity indexa
None
918 (25.6)
(23.9, 27.3)
4164042
6532 (38.4)
<0.0001
1035 (18.7)
(17.5, 19.8)
3117059
7588 (29.8)
<0.0001
0.0001
∗
∗
∗
One
912 (26.0)
(24.4, 27.5)
4225414
3846 (23.7)
1218 (22.3)
(20.9, 23.6)
3721577
5717 (22.9)
∗
∗
∗
Two
662 (18.4)
(16.9, 19.8)
2987313
2488 (15.5)
1083 (19.6)
(18.4, 20.8)
3272605
4243 (17.2)
≥Three
1090 (30.1)
(28.4, 31.7)
4894203
3679 (22.4)
2154 (39.5)
(37.8, 41.2)
6601763
7634 (30.2)
∗
∗
∗
Mean (SE)
1.83 (0.03)
(1.77, 1.90)
1.45 (0.02)
<0.0001
2.23 (0.03)
(2.17, 2.29)
1.84 (0.02)
<0.0001
<0.0001
∗
∗
∗
Chronic health conditions
Diabetes
314 (8.2)
(7.2, 9.1)
1331587
1633 (9.4)
0.021
596 (10.2)
(9.3, 11.2)
1709992
2965 (11.2)
0.106
<0.0001
∗
∗
∗
Kidney disease
57 (1.6)
(1.2, 2.1)
263373
289 (1.6)
0.713
91 (1.5)
(1.2, 1.8)
250872
506 (1.9)
0.047
<0.0001
GI diseaseaa
590 (16.9)
(15.5, 18.3)
2752405
1696 (10.8)
<0.0001
2186 (40.4)
(38.9, 41.9)
6744109
7468 (29.9)
<0.0001
<0.0001
∗
∗
∗
Chronic resp.  conditionsb
615 (16.9)
(15.6, 18.2)
2745606
2144 (13.4)
<0.0001
985 (18.0)
(16.8, 19.3)
3015703
3762 (15.1)
<0.0001
<0.0001
CVDc
257 (7.0)
(6.1, 7.9)
1142025
1078 (6.8)
0.607
393 (7.1)
(6.3, 7.9)
1186819
1829 (7.3)
0.621
<0.0001
Hypertension
1136 (31.1)
(29.4, 32.9)
5064154
4764 (28.7)
0.017
1856 (33.4)
(31.8, 35.0)
5582424
8168 (32.2)
0.165
<0.0001
Dyslipidemia
1159 (32.2)
(30.5, 34.0)
5246236
3977 (24.6)
<0.0001
1881 (33.9)
(32.2, 35.6)
5659527
6628 (26.8)
<0.0001
<0.0001
Liver disease
54 (1.5)
(1.1, 1.9)
244387
198 (1.2)
0.138
91 (1.6)
(1.2, 2.0)
271510
348 (1.3)
0.146
<0.0001
Chronic pain  conditionsd
1836 (51.6)
(49.8, 53.3)
8390744
5940 (36.9)
<0.0001
3018 (55.2)
(53.9, 56.9)
9263106
9943 (39.9)
<0.0001
<0.0001
∗
∗
∗
Mental health  conditionse
832 (23.8)
(22.1, 25.6)
3874783
2623 (16.0)
<0.0001
1674 (30.4)
(28.9, 31.9)
5084683
5854 (22.9)
<0.0001
<0.0001
Insomnia
948 (26.9)
(25.2, 28.7)
4383811
2885 (17.8)
<0.0001
1488 (26.8)
(25.4, 28.2)
4472612
4728 (18.8)
<0.0001
<0.0001
History of cancer
355 (10.1)
(9.0, 11.2)
1638188
1101 (7.4)
<0.0001
569 (10.7)
(9.7, 11.7)
1792043
2039 (8.6)
<0.0001
<0.0001
Use of other complementary health approaches
3539 (98.9)
(98.6, 99.3)
16094998
14150 (86.2)
<0.0001
5357 (97.9)
(97.5, 98.4)
16369136
17689 (72.1)
<0.0001
<0.0001
∗
∗
∗
Other natural  productsf
3331 (93.4)
(92.4, 94.4)
15192940
10243 (64.4)
<0.0001
5215 (95.5)
(94.9, 96.2)
15965914
15806 (64.5)
<0.0001
<0.0001
∗
∗
∗
Mind-bodyg
1870 (53.2)
(51.5, 55.0)
8659604
3621 (23.6)
<0.0001
2094 (39.7)
(38.0, 41.4)
6633294
3290 (13.9)
<0.0001
<0.0001
∗
∗
∗
Manipulative/ bodyworkh
2034 (58.4)
(56.5, 60.3)
9496114
4144 (27.1)
<0.0001
2783 (51.7)
(50.0, 53.4)
8634942
6075 (25.3)
<0.0001
<0.0001
∗
∗
∗
Energy  healing/Reiki
218 (6.1)
(5.2, 7.0)
997157
137 (0.89)
<0.0001
240 (4.5)
(3.8, 5.1)
747014
123 (0.47)
<0.0001
<0.0001
∗
∗
∗
spiritual  practicesi
2334 (64.6)
(62.7, 66.5)
10512222
9637 (56.5)
<0.0001
643 (12.5)
(11.4, 13.5)
2081886
718 (2.9)
<0.0001
<0.0001
∗
∗
∗
Alternative  systemsk
858 (23.8)
(22.1, 25.5)
3867268
1136 (6.9)
<0.0001
1037 (19.0)
(17.8, 20.2)
3180077
1231 (4.9)
<0.0001
<0.0001
∗
∗
∗
Note. Column percentages shown; ∗adjusted for age, sex, and race/ethnicity based on 2000 Census data; ∗∗adjusted for age, sex, and race/ethnicity based on 2010 Census data; ∗∗∗significant changes between 2007 and 2012 indicated by nonoverlapping weighted population confidence intervals; pW values obtained by comparing weighted estimates; note: significant changes between datasets with differing weighting schemes indicated by nonoverlapping weighted population confidence intervals as ∗∗∗; $family costs aside from deductibles, premiums, copays; Rdefined as ≥10 min. increments; aincluding diabetes, kidney disease, gastrointestinal disorder (including ulcer and/or abdominal pain, digestive allergy, and heartburn), respiratory conditions (asthma, emphysema, and/or chronic bronchitis), dyslipidemia, liver condition, rheumatoid arthritis, CVD, hypertension, nonspecific arthritis, gout, migraines, mental health condition; aaincluding bowel conditions and ulcers (2007); past 12 months: abdominal pain, digestive allergy, heartburn, and ever having ulcer (2012); basthma, emphysema, and/or chronic bronchitis; cmyocardial infarction, heart disease, angina pectoris; dmigraines (past 3 months), nonspecific arthritis, gout, nonspecific joint pain for 3+ months, rheumatoid arthritis; edepression, bipolar disorder, phobias, often anxious (past year); fsupplements other than NVNMs, including vitamins/minerals, probiotics (past 30 days), fish oil (past 30 days), chelation therapies; gTai Chi/Qi Gong, yoga, guided imagery, progressive relaxation, deep breathing exercises, meditation (singular term “meditation” used in 2007; expanded in 2012 to include mantra and mindfulness meditation), mindfulness-based stress reduction and cognitive therapy (2012), stress-management class (2007), biofeedback, hypnosis; hpractitioner-based massage (ever), chiropractic/osteopathic manipulation, Sobador visit; iprayed for one’s own health (2007) or centering prayer/contemplative meditation (2012); and/or visit with Espiritista (2007 only), Curandero, Shaman, and/or native American healer; kacupuncture, Ayurveda, homeopathy, and naturopathy.Table 3
NVNM use in two nationally representative samples of adults with diagnosed fibromyalgia, National Health Interview Survey (NHIS 2007N = 221 (1.3%∗C1) versus NHIS 2012 N = 524 (1.7%∗∗C2)).
Characteristic
2007
2012
OverallpW
N (%)
95% CI
Weighted population estimate∗
N (%)
95% CI
Weighted population estimate∗∗
NVNM use ever
<0.0001
∗
∗
∗
Yes
114 (57.1)
(49.3, 64.9)
624881
204 (40.6)
(35.3, 45.8)
633029
No
107 (42.9)
(35.1, 50.7)
469162
320 (59.4)
(54.2, 64.7)
927192
NVNM use in past 12 months
<0.0001
Yes
82 (41.7)
(33.3, 50.2)
456477
157 (31.2)
(26.1, 36.4)
487362
No
139 (58.3)
(49.8, 66.7)
637566
367 (68.8)
(63.6, 73.9)
1072859
NVNM use in past 30 days
<0.0001
Yes
62 (32.7)
(24.6, 40.9)
358265
126 (24.5)
(19.9, 29.1)
382285
No
159 (67.3)
(59.1, 75.4)
735778
398 (75.5)
(70.9, 80.1)
1177936
Number of different NVNM supps in past 30 daystt
(Mean (SE))
0.99 (0.20)
(0.60, 1.4)
1.07 (0.38)
(0.32, 1.8)
0.894
Physician disclosure of NVNMd
<0.0001
Yes
50 (64.6)
(53.1, 76.1)
294988
51 (71.4)
(59.0, 83.9)
140681
No
32 (35.4)
(23.9, 46.9)
161489
15 (28.6)
(16.1, 41.0)
56221
Note. Total sample with fibromyalgia is percentage denominator; ∗adjusted for age, sex, and race/ethnicity based on 2000 Census data; ∗∗adjusted for age, sex, and race/ethnicity based on 2010 Census data; ∗∗∗significant changes between 2007 and 2012 indicated by nonoverlapping weighted population confidence intervals; pW values obtained by comparing weighted estimates; note: significant changes between datasets with differing weighting schemes indicated by nonoverlapping weighted population confidence intervals as ∗∗∗; ttamong NVNM users with fibromyalgia; including combination NVNM supplement; dwithin past 30 days (N = 66; 2007); only disclosure of top therapy assessed within past 12 months (2012); C1(95% CI: 1.1, 1.5); C2(95% CI: 1.6, 1.9).Between 2007 and 2012, rates of NVNM consumption (past 12 months; Table1) declined among non-Hispanic White adults (83% to 79%) but increased among those identified as Hispanic (7% to 9%; p’s < 0.0001). Overall, the likelihood of NVNM use significantly increased by number of health conditions in both years (Table 2; p’s for trend ≤ 0.0001, not shown). In addition, NVNM users (past 12 months) spending under $500 in out-of-pocket medical costs decreased (2007 and 2012: 35.0% and 31.3%, resp.) while NVNM users spending over $3,000 increased (6.2% and 8.3%). This was also noted by an increase in likelihood of NVNM use by out-of-pocket costs for both years (p’s for trend = 0.0001; not shown). Lastly, consumption of other natural products (i.e., vitamins/minerals) increased (93% to 96%) among all herbal users between time points.


### 3.1. Relation of FMS to Herbal Use

Nearly 60% of those with FMS reported previous or current NVNM use; 42% indicated using NVNMs in the past 12 months, and 33% in the past 30 days (Table3). Approximately 3% of all NVNM users had FMS; this rate did not differ between years (Table 4). In 2007, participants with FMS were 3.7 times as likely as those without FMS to use NVNMs for any length of time (OR = 3.7, 95% confidence interval (CI): 2.7, 5.0). After adjustment for demographic, lifestyle, and medical/health factors, those with FMS were 2.7 times as likely to report ever using NVNMs than those without FMS (adjusted odds ratio (AOR) = 2.7, (CI: 1.9, 3.8)). FMS showed a similarly strong positive association to recent NVNM use (12-month and 30-day AORs = 2.3 (CI: 1.5, 3.4) and 2.3 (CI: 1.6, 3.5), resp.). Likewise, FMS was significantly and positively associated with all NVNM use outcomes in 2012, although the magnitude of the associations was lower (2012 AORs: herbal use (ever) = 1.6 (CI: 1.3, 2.0); 12 months = 1.6 (CI: 1.2, 2.0); 30 days = 1.5 (CI: 1.2, 2.0)).Table 4
Association of NVNM use to self-reported fibromyalgia diagnosis in two nationally representative samples of adults, National Health Interview Survey (NHIS 2007,N = 20,127; and 2012, N = 30,672).
N (%)
95% CI
Unadjusted odds ratio (95% CI)
p
Odds ratio adjusted for demographics and related factors∗ (95% CI)
p
Odds ratio adjusted for demographics, lifestyle, and related factors¥ (95% CI)
p
Odds ratio adjusted for demographics, lifestyle, and related factors + comorbidityt (95% CI)
p
NHIS 2007
NVNM use in the last 30 days
Fibromyalgia
Yes
62 (3.0)
(2.1, 3.9)
3.07 (2.12, 4.45)
<0.0001
2.36 (1.59, 3.51)
<0.0001
2.54 (1.69, 3.83)
<0.0001
2.34 (1.55, 3.52)
<0.0001
No
2561 (97.0)
(96.1, 97.9)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
NVNM use in the last 12 months
Fibromyalgia
Yes
82 (2.8)
(2.0, 3.6)
3.09 (2.19, 4.37)
<0.0001
2.34 (1.58, 3.47)
<0.0001
2.48 (1.67, 3.71)
<0.0001
2.25 (1.51, 3.35)
<0.0001
No
3500 (97.2)
(96.4, 98.0)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
NVNM use ever
Fibromyalgia
Yes
114 (2.7)
(2.1, 3.3)
3.66 (2.66, 5.03)
<0.0001
2.85 (2.02, 4.02)
<0.0001
3.01 (2.13, 4.25)
<0.0001
2.66 (1.85, 3.82)
<0.0001
No
4943 (97.3)
(96.7, 97.9)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
NHIS 2012
NVNM use in the last 30 days
Fibromyalgia
Yes
126 (3.0)
(2.4, 3.6)
2.04 (1.59, 2.61)
<0.0001
1.65 (1.27, 2.14)
0.0002
1.72 (1.33, 2.24)
<0.0001
1.51 (1.15, 2.00)
0.003
No
3994 (97.0)
(96.4, 97.6)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
NVNM use in the last 12 months
Fibromyalgia
Yes
157 (2.9)
(2.4, 3.4)
2.03 (1.62, 2.56)
<0.0001
1.72 (1.34, 2.20)
<0.0001
1.82 (1.42, 2.33)
<0.0001
1.57 (1.21, 2.04)
0.0007
No
5333 (97.1)
(96.6, 97.6)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
NVNM use ever
Fibromyalgia
Yes
204 (2.9)
(2.4, 3.3)
2.17 (1.75, 2.69)
<0.0001
1.84 (1.47, 2.32)
<0.0001
1.92 (1.52, 2.42)
<0.0001
1.59 (1.25, 2.03)
0.0002
No
7034 (97.1)
(96.7, 97.6)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
Boldface indicates statistical significance atp≤0.05; ∗adjusted for age, sex, race, education, employment, income, geographic location of birth, insurance status (Medicaid, disability, and private), out-of-pocket medical expenses, delayed access to care due to cost, and region (2007); additionally, marital status (2012); ¥additionally adjusted for smoking status, alcohol use, exercise, and BMI (2007); and substance abuse (2012); thealth conditions include diabetes, kidney disease, gastrointestinal disorder (including ulcer), respiratory conditions, dyslipidemia, liver condition, rheumatoid arthritis, CVD, hypertension, arthritis, gout, migraines, and mental health condition; and self-reported health status.The magnitude of the association of NVNM use to FMS was significantly greater in those with 0-1 comorbid health conditions than in those with 2 or more health conditions (age-adjusted ORs, resp., = 4.7 (CI: 2.2, 9.8) versus 2.8 (CI: 2.0, 3.9;p for interaction = 0.008) in 2007; not shown). However, we found no evidence of a modifying effect of multiple comorbidities in 2012 or for gender in either year.To our knowledge, this is the first large, population-based study to examine the relation of NVNM use to FMS; it is also among the first rigorous studies to investigate the relation of NVNM use to any chronic pain condition in a large sample [25, 29, 30, 36]. Relative to adults without FMS, those with FMS were significantly more likely to report using NVNMs at any time point (within the past 30 days or 12 months or ever) in both 2007 and 2012 survey years; the positive association of FMS to NVNM use remained highly significant even after controlling for a broad array of demographic, lifestyle, and health-related factors.In our study, the majority of those with FMS indicated using NVNMs at some time point; one-third had used NVNMs in the past 30 days. Previous studies assessing herbal use in FMS reported widely varying rates among FMS patients, ranging from 43% (FMS = 434) to 78% (FMS = 90) [36, 37]. Reported rates among other chronic pain populations have been considerably lower, ranging from 6.8% in a sample of primary care patients using opioids [29] to 15% in a primary care patient population with chronic pain [30]. However, percentages given in prior studies were unweighted and may in part reflect differences in study populations and outcome definitions, rendering comparison with our findings challenging.Prevalence of diagnosed FMS increased between 2007 and 2012 (1.3% to 1.7%). Despite lower rates than those appearing globally and in some US studies [1–3], this apparent rise in diagnosed FMS may be due in part to increased recognition of FMS by physicians following publication of the 2010 Preliminary ACR updated criteria for fibromyalgia.In contrast, we found reported NVNM use among adults with FMS declined significantly from 2007 to 2012, paralleling the modest but significant reduction in overall NVNM use observed between these periods. However, the mean number of different combination NVNM supplements used by those with FMS did not differ between time points and averaged lower than that reported in a case-control study of North American women (N=434 with FMS) [36]. In addition, both the observed decline in NVNM use among those with FMS and the positive but more modest association between NVNM use and FMS in 2012 compared to 2007 may also reflect increased availability of FDA-approved FMS medications following the 2007 NHIS survey administration. It also remains possible that both the increase in FMS diagnoses and decrease in odds of NVNM use for FMS over time are also in part the result of promotion for FMS drugs by pharmaceutical companies [38] and increased off-label prescription of other drugs for FMS, potentially including opioids [39, 40].Strengths and Limitations. This investigation was the first study to assess the relation between NVNM use and FMS in a large US population. Strengths of our study include large, nationally representative samples, use of data from two time periods, and the availability of comprehensive information on NVNM use, as well as a broad array of demographic, lifestyle, health-related, and other potentially confounding factors. However, there were some limitations. Perhaps most important, the cross-sectional study design precluded determination of causal relationships. Ascertainment of NVNM use and medical history, including diagnosis of FMS, was reliant on self-report, raising the possibility of recall bias; however, potential underascertainment would likely bias our results toward the null, indicating more conservative estimates.Although the NVNM use outcome mainly comprised of herbal dietary supplements and was assessed separately from many other nonherbal supplements in both NHIS data collection periods, the nonherbal products coenzyme Q-10, SAM-e, fish oil, and prebiotics/probiotics were included in our main NVNM outcome. Thus, our consideration of a broader NVNM outcome may be more appropriate than a specific herbal supplement use outcome, since reports of individual ingredients were not consistently available between years. There was inadequate capture of certain herbal products within the NVNM outcome. No data were available on consumption of herbal and green teas used for health purposes or on products not labelled (per NHIS requirements for inclusion) “dietary supplement,” including home grown herbs, traditionally prepared herbal products, and bulk herbs/powders sometimes recommended (i.e., by nutritionists, natural foods purveyors) over widely available supplements due to quality and processing concerns. We did not have information on FMS severity or duration, and although the 2012 questionnaire differed from 2007, there were no differences with respect to assessment of fibromyalgia. Based on cognitive testing and input from expert panels, the definitions of certain modalities were modified in 2012 to reduce false-positive responses [34] which may have affected findings. However, these changes were relatively minor and were unlikely to affect our estimates, as these potential false-positives did not vary by disease status.Given the high prevalence rates of those with FMS using NVNMs, and the strong, positive relationship of FMS to NVNM use which persisted in 2012 despite the availability of approved treatments, additional prospective research is warranted to confirm these findings, to further investigate the prevalence, patterns, and determinants of specific NVNM use in FMS, and to explore the safety and potential efficacy of NVNM products for this still poorly managed condition.


## 3.1. Relation of FMS to Herbal Use

Nearly 60% of those with FMS reported previous or current NVNM use; 42% indicated using NVNMs in the past 12 months, and 33% in the past 30 days (Table3). Approximately 3% of all NVNM users had FMS; this rate did not differ between years (Table 4). In 2007, participants with FMS were 3.7 times as likely as those without FMS to use NVNMs for any length of time (OR = 3.7, 95% confidence interval (CI): 2.7, 5.0). After adjustment for demographic, lifestyle, and medical/health factors, those with FMS were 2.7 times as likely to report ever using NVNMs than those without FMS (adjusted odds ratio (AOR) = 2.7, (CI: 1.9, 3.8)). FMS showed a similarly strong positive association to recent NVNM use (12-month and 30-day AORs = 2.3 (CI: 1.5, 3.4) and 2.3 (CI: 1.6, 3.5), resp.). Likewise, FMS was significantly and positively associated with all NVNM use outcomes in 2012, although the magnitude of the associations was lower (2012 AORs: herbal use (ever) = 1.6 (CI: 1.3, 2.0); 12 months = 1.6 (CI: 1.2, 2.0); 30 days = 1.5 (CI: 1.2, 2.0)).Table 4
Association of NVNM use to self-reported fibromyalgia diagnosis in two nationally representative samples of adults, National Health Interview Survey (NHIS 2007,N = 20,127; and 2012, N = 30,672).
N (%)
95% CI
Unadjusted odds ratio (95% CI)
p
Odds ratio adjusted for demographics and related factors∗ (95% CI)
p
Odds ratio adjusted for demographics, lifestyle, and related factors¥ (95% CI)
p
Odds ratio adjusted for demographics, lifestyle, and related factors + comorbidityt (95% CI)
p
NHIS 2007
NVNM use in the last 30 days
Fibromyalgia
Yes
62 (3.0)
(2.1, 3.9)
3.07 (2.12, 4.45)
<0.0001
2.36 (1.59, 3.51)
<0.0001
2.54 (1.69, 3.83)
<0.0001
2.34 (1.55, 3.52)
<0.0001
No
2561 (97.0)
(96.1, 97.9)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
NVNM use in the last 12 months
Fibromyalgia
Yes
82 (2.8)
(2.0, 3.6)
3.09 (2.19, 4.37)
<0.0001
2.34 (1.58, 3.47)
<0.0001
2.48 (1.67, 3.71)
<0.0001
2.25 (1.51, 3.35)
<0.0001
No
3500 (97.2)
(96.4, 98.0)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
NVNM use ever
Fibromyalgia
Yes
114 (2.7)
(2.1, 3.3)
3.66 (2.66, 5.03)
<0.0001
2.85 (2.02, 4.02)
<0.0001
3.01 (2.13, 4.25)
<0.0001
2.66 (1.85, 3.82)
<0.0001
No
4943 (97.3)
(96.7, 97.9)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
NHIS 2012
NVNM use in the last 30 days
Fibromyalgia
Yes
126 (3.0)
(2.4, 3.6)
2.04 (1.59, 2.61)
<0.0001
1.65 (1.27, 2.14)
0.0002
1.72 (1.33, 2.24)
<0.0001
1.51 (1.15, 2.00)
0.003
No
3994 (97.0)
(96.4, 97.6)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
NVNM use in the last 12 months
Fibromyalgia
Yes
157 (2.9)
(2.4, 3.4)
2.03 (1.62, 2.56)
<0.0001
1.72 (1.34, 2.20)
<0.0001
1.82 (1.42, 2.33)
<0.0001
1.57 (1.21, 2.04)
0.0007
No
5333 (97.1)
(96.6, 97.6)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
NVNM use ever
Fibromyalgia
Yes
204 (2.9)
(2.4, 3.3)
2.17 (1.75, 2.69)
<0.0001
1.84 (1.47, 2.32)
<0.0001
1.92 (1.52, 2.42)
<0.0001
1.59 (1.25, 2.03)
0.0002
No
7034 (97.1)
(96.7, 97.6)
1.00 (reference)
1.00 (reference)
1.00 (reference)
1.00 (reference)
Boldface indicates statistical significance atp≤0.05; ∗adjusted for age, sex, race, education, employment, income, geographic location of birth, insurance status (Medicaid, disability, and private), out-of-pocket medical expenses, delayed access to care due to cost, and region (2007); additionally, marital status (2012); ¥additionally adjusted for smoking status, alcohol use, exercise, and BMI (2007); and substance abuse (2012); thealth conditions include diabetes, kidney disease, gastrointestinal disorder (including ulcer), respiratory conditions, dyslipidemia, liver condition, rheumatoid arthritis, CVD, hypertension, arthritis, gout, migraines, and mental health condition; and self-reported health status.The magnitude of the association of NVNM use to FMS was significantly greater in those with 0-1 comorbid health conditions than in those with 2 or more health conditions (age-adjusted ORs, resp., = 4.7 (CI: 2.2, 9.8) versus 2.8 (CI: 2.0, 3.9;p for interaction = 0.008) in 2007; not shown). However, we found no evidence of a modifying effect of multiple comorbidities in 2012 or for gender in either year.To our knowledge, this is the first large, population-based study to examine the relation of NVNM use to FMS; it is also among the first rigorous studies to investigate the relation of NVNM use to any chronic pain condition in a large sample [25, 29, 30, 36]. Relative to adults without FMS, those with FMS were significantly more likely to report using NVNMs at any time point (within the past 30 days or 12 months or ever) in both 2007 and 2012 survey years; the positive association of FMS to NVNM use remained highly significant even after controlling for a broad array of demographic, lifestyle, and health-related factors.In our study, the majority of those with FMS indicated using NVNMs at some time point; one-third had used NVNMs in the past 30 days. Previous studies assessing herbal use in FMS reported widely varying rates among FMS patients, ranging from 43% (FMS = 434) to 78% (FMS = 90) [36, 37]. Reported rates among other chronic pain populations have been considerably lower, ranging from 6.8% in a sample of primary care patients using opioids [29] to 15% in a primary care patient population with chronic pain [30]. However, percentages given in prior studies were unweighted and may in part reflect differences in study populations and outcome definitions, rendering comparison with our findings challenging.Prevalence of diagnosed FMS increased between 2007 and 2012 (1.3% to 1.7%). Despite lower rates than those appearing globally and in some US studies [1–3], this apparent rise in diagnosed FMS may be due in part to increased recognition of FMS by physicians following publication of the 2010 Preliminary ACR updated criteria for fibromyalgia.In contrast, we found reported NVNM use among adults with FMS declined significantly from 2007 to 2012, paralleling the modest but significant reduction in overall NVNM use observed between these periods. However, the mean number of different combination NVNM supplements used by those with FMS did not differ between time points and averaged lower than that reported in a case-control study of North American women (N=434 with FMS) [36]. In addition, both the observed decline in NVNM use among those with FMS and the positive but more modest association between NVNM use and FMS in 2012 compared to 2007 may also reflect increased availability of FDA-approved FMS medications following the 2007 NHIS survey administration. It also remains possible that both the increase in FMS diagnoses and decrease in odds of NVNM use for FMS over time are also in part the result of promotion for FMS drugs by pharmaceutical companies [38] and increased off-label prescription of other drugs for FMS, potentially including opioids [39, 40].Strengths and Limitations. This investigation was the first study to assess the relation between NVNM use and FMS in a large US population. Strengths of our study include large, nationally representative samples, use of data from two time periods, and the availability of comprehensive information on NVNM use, as well as a broad array of demographic, lifestyle, health-related, and other potentially confounding factors. However, there were some limitations. Perhaps most important, the cross-sectional study design precluded determination of causal relationships. Ascertainment of NVNM use and medical history, including diagnosis of FMS, was reliant on self-report, raising the possibility of recall bias; however, potential underascertainment would likely bias our results toward the null, indicating more conservative estimates.Although the NVNM use outcome mainly comprised of herbal dietary supplements and was assessed separately from many other nonherbal supplements in both NHIS data collection periods, the nonherbal products coenzyme Q-10, SAM-e, fish oil, and prebiotics/probiotics were included in our main NVNM outcome. Thus, our consideration of a broader NVNM outcome may be more appropriate than a specific herbal supplement use outcome, since reports of individual ingredients were not consistently available between years. There was inadequate capture of certain herbal products within the NVNM outcome. No data were available on consumption of herbal and green teas used for health purposes or on products not labelled (per NHIS requirements for inclusion) “dietary supplement,” including home grown herbs, traditionally prepared herbal products, and bulk herbs/powders sometimes recommended (i.e., by nutritionists, natural foods purveyors) over widely available supplements due to quality and processing concerns. We did not have information on FMS severity or duration, and although the 2012 questionnaire differed from 2007, there were no differences with respect to assessment of fibromyalgia. Based on cognitive testing and input from expert panels, the definitions of certain modalities were modified in 2012 to reduce false-positive responses [34] which may have affected findings. However, these changes were relatively minor and were unlikely to affect our estimates, as these potential false-positives did not vary by disease status.Given the high prevalence rates of those with FMS using NVNMs, and the strong, positive relationship of FMS to NVNM use which persisted in 2012 despite the availability of approved treatments, additional prospective research is warranted to confirm these findings, to further investigate the prevalence, patterns, and determinants of specific NVNM use in FMS, and to explore the safety and potential efficacy of NVNM products for this still poorly managed condition.


## 4. Conclusions

In the first large cross-sectional study of two nationally representative samples of US adults, reported diagnosis of FMS was strongly and positively associated with NVNM use in both 2007 and 2012 after adjustment for demographic, lifestyle, and health factors. Rigorous prospective studies are needed to confirm these findings and to further explore the patterns, determinants, and potential efficacy of NVNM use in those with FMS.



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*Source: 6751856-2017-07-25.xml*