Original Article

J Endocrinol Metab. 2020;10(1):8-15

Relation Between Daily Self-Weighing and Physique,Lifestyle Factors, and Glycemic Parameters inJapanese College Students
Tetsuya Kakumaa, d, Seiko Arikib, Yuichi Yoshidab, Hirotaka Shibatab,
Takashi Tsutsumic, Yoshikuni Kudoc

Abstract
Background: The impact of self-weighing on young adults attending college has not been fully clarified. The present study aimed to
examine self-weighing behavior and associated gender differences inJapanese college students and investigate the relation between habitual daily self-weighing and physique, lifestyle factors and glycemicparameters.
Methods: We retrospectively evaluated data from a 75-g oral glucose
tolerance test (OGTT) that was performed during clinical training of
medical students between 2010 and 2014. Information concerning
physique (e.g. body weight and waist circumference) and a lifestylefocused questionnaire were completed before the OGTT. Participants
comprised 441 fifth-grade university students (279 males and 162 females) from the Oita University Faculty of Medicine.
Results: A total of 26.8% of participants were habitual self-weighers.
Females were significantly more likely to engage in habitual selfweighing than males. There were no significant differences in glucose
metabolism between individuals who regularly weighed themselves
and those who did not in either gender. Factors related to the performance of daily self-weighing were not skipping breakfast in males
and regular exercise in females.
Conclusions: Although there was no meaningful relation between
habitual self-weighing and glucose metabolism in this study, eating
breakfast regularly and exercising regularly independently promoted
self-weighing behavior in males and females, respectively. Thesefindings suggest that these common practices may be helpful for colManuscript submitted December 18, 2019, accepted December 23, 2019aHealth Support Center, Hasama Campus, Oita University, Yufu City, Oita
879-5593, JapanbDepartment of Endocrinology, Metabolism, Rheumatology and Nephrology,
Faculty of Medicine, Oita University, Yufu City, Oita 879-5593, JapancHealth Support Center, Dannoharu Campus, Oita University, Oita City, Oita
870-1192, JapandCorresponding Author: Tetsuya Kakuma, Health Support Center, HasamaCampus, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita 8795593, Japan. Email: kakuma@oita-u.ac.jp

doi: https://doi.org/10.14740/jem633

8lege students as a method to encourage habitual daily self-weighing,consequently providing a healthy environment in college life to prevent potential obesity-related diseases.
Keywords: Self-weighing; College student; Glucose metabolism;
Gender difference; Not skipping breakfast; Regular exercise

Introduction
Postadolescent university students are young adults in a developmental period associated with various lifestyle changes. The
transition from puberty to adulthood often triggers unhealthy
behaviors such as binge drinking, skipping breakfast and poor
sleep habits. These changes are known to contribute to weightgain [1]. Weight control during this transitional period has animportant implication for the pathogenesis of lifestyle-relateddiseases associated with obesity [2]. Most reports regarding
self-weighing indicate that this behavior is a positive strategy
for the treatment and prevention of obesity in adults [3, 4].
Frequent self-weighing has been associated with weight gain
prevention as well as weight loss and weight loss maintenance.
This behavior has also been associated with greater weight loss
in younger generations with obesity [5] and healthy weight
management in participants with normal weight [6]. The
metabolic parameters of individuals who practice regular selfweighing may be better than those of individuals who do notpractice self-weighing. Our previous study showed that daily
self-weighing contributes to favorable glycemic control independent of prospective weight loss [7]. This finding suggeststhat a habit of self-weighing per se might be associated withimproved glucose metabolism even though self-monitoring ofbody weight was not used as an intervention strategy. However, few studies have examined the relation between glucose
metabolism and self-weighing as a habitual practice as opposed to a therapeutic strategy.
Moreover, the actual situation of self-weighing in young
adults attending college has not been fully clarified, especiallyin Japan. A white paper was written about the current healthstate of university students based on various information obtained from regular health examinations in Japanese national universities in 2015 [8]. Recent data from approximately

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This article is distributed under the terms of the Creative Commons Attribution Non-Commercial 4.0 International License, which permits
unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly citedKakuma et al

J Endocrinol Metab. 2020;10(1):8-15

440,000 university students showed the percentage with certain daily habits (e.g. smoking, drinking and regular exercise) and reported a relationship between eating breakfast andsmoking rates, drinking rates, habitual exercise, and sleeping
time as well as an association between such lifestyle factors
and physical examination parameters (e.g. body mass index(BMI), blood pressure and heart rate) [8]. However, to the bestof our knowledge, no previous studies in young adults have examined the relation between habitual self-weighing and physique, lifestyle factors and glycemic parameters obtained froman oral glucose tolerance test (OGTT).
The present study aimed to provide more information on
self-weighing in young adults attending college by examining
1) the current status of self-weighing behavior and related gender differences and 2) the relation between daily self-weighing
and physique, lifestyle factors, and glycemic parameters obtained from a 75-g OGTT. Findings from this study may help
with the introduction of a unique approach for medical staff
at health support centers in universities to help students avoid
future obesity-related lifestyle diseases.

evening once a day and more than once a day) or no (none).
The rare cases of self-weighing less than once a day, such as
weekly or monthly, were combined into the “none” category.
Gender, age, height and weight were self-reported. Waist circumference at the umbilical level was measured by a fellow
medical student in the late exhalation phase according to therecommendation proposed by the Japanese Committee for the
diagnostic criteria of metabolic syndrome [9].
After confirming that the participating students did not eat
and drink after 11 pm on the previous day, and that they had
skipped breakfast on the day of the OGTT, blood samples werecollected by a fellow medical student at 0, 30, 60 and 120 min,according to a standard 75-g OGTT protocol [10]. Participants
were given instructions on OGTT training at a meeting the day
before the test. Clinical practice leaders taught the students
how to draw blood from a vein. This practical training wascompleted on the morning of the OGTT.

Materials and Methods

Plasma glucose and insulin levels were measured using standard laboratory procedures at the clinical laboratory at Oita
University Hospital. Insulin resistance and secretion were
determined by homeostasis model assessment [11] based on
fasting plasma glucose and insulin values: homeostasis model
assessment of insulin resistance (HOMA-IR) = fasting glucose(mg/dL) × fasting insulin (µU/mL)/405; homeostasis model
assessment of beta cell function (HOMA-β) = 360 × fasting
insulin (µU/mL)/fasting glucose (mg/dL) - 63. The insulinogenic index was calculated as the following incremental ratio:Δinsulin/Δglucose = insulin at 30 min (µU/mL) - fasting insulin (µU/mL)/glucose at 30 min (mg/dL) - fasting glucose (mg/dL). The area under the curve (AUC) for glucose and insulin during the OGTT was calculated with the trapezoidal rule.
The glucose tolerance category was determined according to
the Japanese Diabetes Association criteria for the 75-g OGTT
[12]: diabetes was defined as fasting glucose ≥ 126 mg/dL and/or 2-h glucose ≥ 200 mg/dL, impaired glucose tolerance (IGT)
was defined as fasting glucose ≥ 110 mg/dL but < 126 mg/dL
and/or 2-h glucose ≥ 140 mg/dL but < 200 mg/dL, and normal
glucose tolerance was defined as fasting glucose < 110 mg/dL
and 2-h glucose < 140 mg/dL. BMI was calculated as weight(kg) divided by height squared (m2). Obesity was characterized by a BMI ≥ 25 kg/m2, and abdominal obesity was defined
as a waist circumference ≥ 85 cm in males and ≥ 90 cm infemales [9].

Subjects
We retrospectively evaluated data from a 75-g OGTT performed during clinical training for medical students at Oita
University Faculty of Medicine between 2010 and 2014. Selfreported information concerning physique (e.g. body weight
and waist circumference) and a lifestyle-focused questionnaire
were collected before administration of an OGTT. Participants
comprised 441 fifth-grade university students (279 males and
162 females). Informed consent for the OGTT and for collecting information concerning physique and lifestyle behaviors
was obtained from all students while in school. The present
study was conducted in accordance with the Declaration of
Helsinki and was carried out with the approval of the Ethics
Committee of Oita University (date of approval: January 16,
2017, approval number: 1146).
Assessment of variables
A questionnaire regarding lifestyle behaviors was administered to all participating students the day before the OGTT.
Current smoking was classified as yes or no (including nonsmokers and past smokers). Regular exercise was classified
as yes (member of an athletic club or exercising more than 3days during a week) or no. Alcohol drinking was classified as
yes (including occasional drinkers and drinking more than 1
day a week) or no (nondrinker). Skipping breakfast was classified as yes (no breakfast more than 3 days a week) or no.
Frequently eating late at night was classified as yes (night eating after 10 pm more than 3 days a week) or no. Excessive softdrink consumption was classified as yes (more than 500 mL ofsoft drink intake more than 3 days a week) or no. Daily selfweighing was classified as yes (including morning once a day,Laboratory measurements

Statistical analysis
Because all values were not normally distributed, data are expressed as medians (25th - 75th percentiles) and were nonparametrically compared between groups using the Wilcoxon
rank-sum test. Differences in proportions were compared using
the χ2 test or Fisher’s exact probability test. Univariate logistic
regression analysis was used to investigate the relations between habitual daily self-weighing and clinical characteristics.

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9Self-Weighing in Japanese Medical Students

J Endocrinol Metab. 2020;10(1):8-15

Table 1. Clinical Characteristics and Lifestyle Profiles of Study Participants
Male

FemaleP value

Number279

162

Age (years)

24.0 (23.0 - 26.0)

23.0 (23.0 - 25.0)

0.022

Height (cm)171.0 (168.0 - 175.0)

159.0 (155.2 - 162.0)< 0.001

Weight (kg)64.0 (59.0 - 70.0)

50.0 (47.0 - 53.0)< 0.001

BMI (kg/m2)

21.6 (20.3 - 23.0)

19.8 (18.6 - 20.7)< 0.001

Waist circumference (cm)77.0 (73.0 - 82.0)

70.4 (65.8 - 74.0)< 0.001

Fasting plasma glucose (mg/dL)

85.0 (80.0 - 90.0)

84.0 (79.0 - 88.0)

0.017

30 min plasma glucose (mg/dL)

132.0 (114.0 - 147.0)

123.0 (103.0 - 135.0)< 0.001

60 min plasma glucose (mg/dL)

108.0 (91.0 - 130.0)

97.5 (84.0 - 115.3)< 0.001

120 min plasma glucose (mg/dL)

92.0 (81.0 - 107.0)

96.0 (80.8 - 110.0)

0.590

Fasting plasma insulin (µU/mL)

5.6 (4.2 - 7.5)

5.4 (4.2 - 7.1)

0.440

30 min plasma insulin (µU/mL)

40.1 (28.1 - 58.7)

42.2 (32.5 - 62.5)

0.041

60 min plasma insulin (µU/mL)

30.8 (20.7 - 44.1)

34.6 (25.4 - 47.8)

0.020

120 min plasma insulin (µU/mL)

22.4 (14.1 - 32.5)

30.4 (22.8 - 39.8)< 0.001

HOMA-IR

1.17 (0.87 - 1.56)

1.11 (0.87 - 1.46)

0.265

HOMA-β94.3 (69.0 - 124.9)

94.1 (74.4 - 128.3)

0.310

Insulinogenic index (Δinsulin30/Δglucose30)

0.77 (0.48 - 1.27)

1.08 (0.62 - 1.83)< 0.001

AUC-glucose during OGTT (mg × min/dL × 103)12.8 (11.5 - 14.6)

12.0 (10.7 - 13.6)

0.001

AUC-insulin during OGTT (µU × min/dL × 103)

3.6 (2.6 - 4.6)

4.0 (3.1 - 5.2)

< 0.001

Daily self-weighing

56 (20.1)

62 (38.3)< 0.001

Regular exercise

165 (59.1)

46 (28.4)< 0.001

Alcohol drinking

252 (90.3)

143 (88.3)

0.520

Skipping breakfast

88 (31.5)

43 (26.5)

0.282

Frequently eating late at night69 (24.7)

17 (10.5)< 0.001

Excess soft drink consumption

78 (28.0)

12 (7.4)< 0.001

Figures in parentheses are interquartile ranges (25th - 75th percentiles) or n (%). BMI: body mass index; HOMA-IR: homeostasis model assessmentof insulin resistance; HOMA-β: homeostasis model assessment of beta-cell function; AUC: area under the curve; OGTT: oral glucose tolerance test.

Lifestyle statuses were represented by dummy variables (1 =yes, 0 = no). Next, multivariate logistic regression analysis
was conducted to examine factors possibly affecting habitual
daily self-weighing. To build this model, factors with P < 0.1
in the univariate logistic regression analysis were included in
the multivariate analysis. For clinical usability of the gendercomparison, weight (as opposed to BMI and/or waist circumference), was selected as the explanatory variable for physique. Statistical analyses were performed using JMP software
programs (version 12.0.1 for Macintosh, SAS Institute Inc.,
Cary, NC, USA). A P value < 0.05 (two-sided) was consideredsignificant.

Results
Clinical characteristics and lifestyle profiles
Clinical characteristics and lifestyle profiles of the participants10

are shown in Table 1. Males were significantly older than females (P < 0.05) and had a significantly greater height, weight,
BMI and waist circumference (P < 0.001, P < 0.001, P < 0.001
and P < 0.001, respectively). A total of 18.6% of males werediagnosed with abdominal obesity; however, none of the females met that classification (data not shown). The fasting
plasma glucose, 30-min postload glucose, 60-min postload
glucose and AUC-glucose during the OGTT were significantly greater in males (P < 0.05, P < 0.001, P < 0.001 and P< 0.005, respectively), and the 30-min postload insulin, 60min postload insulin, 120-min postload insulin, insulinogenic
index and AUC-insulin during the OGTT were significantly
greater in females (P < 0.05, P < 0.05, P < 0.001, P < 0.001 and
P < 0.001, respectively). There were no significant differencesin HOMA-IR or -β between males and females. IGT was identified in 4.7% of males and 3.7% of females; however, there
was no significant difference in the prevalence of IGT between
the genders. A total of 26.8% of participants reported weighing
themselves at least once a day. These individuals were defined
as having a habit of daily self-weighing. Self-weighing fre-

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Kakuma et al

J Endocrinol Metab. 2020;10(1):8-15

quency was significantly higher in females than in males (P <0.001). The proportions of current smoking (data not shown),
regular exercise, frequently eating late at night and excessive
soft drink consumption were significantly greater in males thanin females (P < 0.001, P < 0.001 and P < 0.001, respectively).
Only one female in the study was a current smoker. Because
she could be easily identified, data regarding current smoking
were omitted from the tables on ethical grounds.
Clinical characteristics and lifestyle factors according todaily self-weighing
When students were divided according to whether or not they
performed daily self-weighing (Table 2), the weight, BMI andwaist circumference of participants were significantly higher
in the self-weighing group in males (P < 0.005, P < 0.001 and P< 0.005, respectively), whereas in females, a trend was shown
only for weight and BMI. There were no significant differences between the groups according to self-weighing status (P= 0.062 and P = 0.064, respectively). In males, the percentageof participants who skipped breakfast was significantly lower
in the self-weighing group (P < 0.05), whereas in females, theself-weighing group was significantly younger and participated in significantly more physical activity than the non-selfweighing group (P < 0.05 and P < 0.05, respectively). There
were no significant differences in glucose metabolism between
the groups in either gender.
Relation between clinical characteristics and lifestyle withdaily self-weighing
Because the clinical characteristics and lifestyle profiles weresignificantly different between the male and female students,
the relation of age, physique and lifestyle with daily selfweighing was examined by gender using logistic regression
analysis. Regarding the variables for physique, we used weightbecause it is not necessary to calculate, and the changes perunit are easy to assess. In males, daily self-weighing was significantly associated with age, weight and skipping breakfast(P < 0.05, P < 0.01 and P < 0.05, respectively) (Table 3). The
odds ratio for skipping breakfast was the lowest among thosefactors. Multivariate logistic regression analysis was conducted to investigate the association between daily self-weighing
and skipping breakfast after adjusting for potential confounders, including age and frequently eating late at night. Skipping
breakfast was independently and negatively related to daily
self-weighing in males (P < 0.05). In addition, weight wasalso independently and significantly associated with daily selfweighing in males (P < 0.05).
In females, daily self-weighing was significantly associated with current weight and regular exercise (P < 0.05 and P <0.01, respectively) (Table 4). The odds ratio of regular exercise
was two-fold higher than that of current weight. To investigate the association between daily self-weighing and regularexercise, multivariate logistic regression analysis was also performed after adjusting for potential confounders, including age

and skipping breakfast. Regular exercise was independently
and positively related to daily self-weighing in females (P <0.05).

Discussion
The main findings of the present study are as follows. 1) A
total of 26.8% of college students enrolled in the present study
were habitual self-weighers who weighed themselves at least
once daily. Females were more likely to report self-weighing
behaviors than males. 2) In young adults attending college,
there were no significant differences in glucose metabolism
between groups with and without self-weighing habits. The
current weight of the participants was significantly higher inthe self-weighing group in males, while in females, results
showed only a trend for this variable. Factors related to daily
self-weighing were not skipping breakfast and weight gain inmales and exercise habits in females.
There are few reports about the importance of “daily”
self-weighing for health management, especially in college
students. In Western countries, the proportion of daily selfweighing was reported to be less than 5% in young adults (n =2,287, mean age = 25.3, female = 55.0%, overweight or obese= 51.5%) [13] and approximately 11% in working adults (n =2,732) [14]. Daily self-weighers comprised 26.8% of the students in this study (n = 441, mean age = 24.8, female = 36.7%,
mean BMI = 21.2), and the percentage was almost the same asthat (25.2%) in our previous report (n = 306, mean age = 62.3,
female = 37.3%, mean BMI = 24.6) that assessed daily selfweighing in patients with type 2 diabetes [7]. The Health Support Center at Tokai University also reported that daily selfweighers comprised almost 23% of the participants enrolled ina health investigation [15]. In general, it appears that Japanesepeople are likely to weigh themselves more frequently thanWestern people. This may represent a fundamental differencein lifestyle behavior for health management between Japanand Western countries.
The prevalence of daily self-weighing was higher in females (31%) than in males (15%) in Tokai University’s report
related to working adults described above [15]. In college students, the ratio of daily self-weighing between females andmales in our study was almost the same (38.3% vs. 20.1%,
respectively) as that noted in working adults and was similar
to the estimates of daily self-weighing among Western young
adults (6.3% of females and 2.7% of males) [13]. The high rate
in females may be due to a high level of interest in body image;
however, there were no significant differences in body weight
between groups with and without self-weighing habits in thisstudy. In males, body weight and waist circumference weresignificantly higher in the group with self-weighing habits, andcurrent weight per se was a significant independent promoterof daily self-weighing in males. These findings imply males
are preoccupied with their bodies. However, it is possible thatthe high rate of self-weighing in females had already prevented
weight gain in this group. Although the reasons the prevalenceof daily self-weighing was higher in females than in males
were not clarified in the present study, it may be interesting to

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11

12
51 (91.1)
10 (17.9)9 (16.1)
12 (21.4)

Alcohol drinking

Skipping breakfast

Frequently eating late at night

Excess soft drink consumption

66 (29.6)

60 (26.9)

78 (35.0)201 (90.1)

128 (57.4)

3.6 (2.6 - 4.7)

12.9 (11.5 - 14.6)

0.76 (0.46-1.26)

93.3 (66.5 - 125.1)

1.19 (0.87 - 1.53)

76.0 (72.5 - 81.4)

21.3 (20.1 - 22.9)

63.0 (58.0 - 70.0)

172.0 (168.0 - 175.5)

24.0 (23.0 - 25.0)

223

No

0.248

0.119

0.015

1.000

0.288

0.733

0.806

0.367

0.570

0.844

0.002

<0.001

0.002

0.330

0.515

P value

3 (4.8)6 (9.7)12 (19.4)

55 (88.7)

25 (40.3)

4.1 (3.2 - 5.3)

12.4 (11.1 - 13.8)

1.05 (0.62 - 1.83)

100.3 (76.8 - 130.6)

1.13 (0.89 - 1.41)

70.5 (67.0 - 73.6)

20.0 (19.1 - 20.8)

51.0 (48.0 - 54.0)

159.0 (157.0 - 162.0)

23.0 (22.0 - 24.0)

62

Yes

9 (9.0)11 (11.0)

31 (31.0)

88 (88.0)

21 (21.0)

4.0 (3.1 - 5.1)

11.9 (10.6 - 13.5)

1.11 (0.62 - 1.77)

89.8 (72.5 - 124.5)

1.09 (0.85 - 1.50)

70.2 (65.0 - 74.0)

19.6 (18.5 - 20.7)

50.0 (46.0 - 52.4)

159.5 (154.0 - 163.0)

24.0 (23.0 - 25.0)

100

No

0.375

1.000

0.143

1.000

0.012

0.639

0.213

0.782

0.374

0.908

0.665

0.064

0.062

0.723

0.036

P value

Habitual daily self-weighing; female (N = 162)

Figures in parentheses are interquartile ranges (25th - 75th percentiles) or n (%). BMI: body mass index; HOMA-IR: homeostasis model assessment of insulin resistance; HOMA-β:homeostasis model assessment of beta-cell function; AUC: area under the curve; OGTT: oral glucose tolerance test.

37 (66.1)

96.3 (71.1 - 123.5)

HOMA-β3.7 (2.7 - 4.4)

1.12 (0.86 - 1.64)

HOMA-IR

Regular exercise

79.5 (75.2 - 86.5)

Waist circumference (cm)

AUC-insulin during OGTT (µU × min/dL × 103)22.7 (21.5 - 24.5)

BMI (kg/m2)

0.82 (0.50 - 1.52)

67.0 (62.1 - 71.0)

Weight (kg)12.7 (11.6 - 14.7)

171.0 (167.3 - 174.0)

Height (cm)

AUC-glucose during OGTT (mg × min/dL × 103)24.0 (23.0 - 28.0)

Age (years)

Insulinogenic index (Δinsulin30/Δglucose30)

56

Yes

NumberHabitual daily self-weighing; male (N = 279)

Table 2. Comparison of Clinical Characteristics and Lifestyle Profiles in Male and Female College Students With or Without Daily Self-Weighing

Self-Weighing in Japanese Medical Students
J Endocrinol Metab. 2020;10(1):8-15

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0.31 - 1.27

0.214

0.082

0.010

0.831

0.234

0.009

0.038

P value

0.44

1.04

1.05

Odds ratio

0.20 - 0.90

1.00 - 1.08

0.98 - 1.12

95% CI

Model 1

0.024

0.027

0.149

P value

0.60

0.48

1.04

1.05

Odds ratio

Multivariate logistic regression

0.26 - 1.31

0.21 - 0.99

1.00 - 1.07

0.99 - 1.12

95% CI

Mode 2

0.207

0.048

0.033

0.127

P value

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1.06
2.54
1.07
0.53
0.87
0.51

WeightRegular exercise

Alcohol drinking

Skipping breakfast

Frequently eating late at night

Excess soft drink consumption

0.11 - 1.80

0.28 - 2.41

0.24 - 1.12

0.41 - 3.03

1.27 - 5.16

1.00 - 1.12

0.75 - 1.01

95% CI

0.312

0.789

0.098

0.891

0.009

0.048

0.075

P value

2.27

1.04

Odds ratio

1.11 - 4.68

0.98 - 1.11

95% CI

Model 1

0.025

0.156

P value

0.45

2.33

1.05

0.92

Odds ratio

Multivariate logistic regression

0.19 - 1.00

1.10 - 5.01

0.99 - 1.12

0.77 - 1.06

95% CI

Model 2

0.051

0.027

0.094

0.236

P valueSignificant predictors of daily self-weighing were explored among five parameters: regular exercise, alcohol drinking, skipping breakfast, frequently eating late at night and excess softdrink consumption (yes = 1, no = 0). Model 1: regular exercise and weight. Model 2: regular exercise, weight, age and skipping breakfast. CI: confidence interval.

0.88

Age

Odds ratio

Univariate logistic regression

Table 4. Logistic Regression Analysis With Daily Self-Weighing as the Dependent Variable in Females

Significant predictors of daily self-weighing were explored among five parameters: regular exercise, alcohol drinking, skipping breakfast, frequently eating late at night and excess softdrink consumption (yes = 1, no = 0). Model 1: skipping breakfast, weight and age. Model 2: skipping breakfast, weight, age and frequently eating late at night. CI: confidence interval.

0.65

Excess soft drink consumption

0.23 - 1.08

0.18 - 0.81

0.40
0.52

0.79 - 2.71
0.43 - 3.46

1.45
1.12

Regular exercise

Alcohol drinking

Skipping breakfast

1.00 - 1.14
1.01 - 1.08

1.07
1.05

Age

WeightFrequently eating late at night

95% CI

Odds ratio

Univariate logistic regression

Table 3. Logistic Regression Analysis With Daily Self-Weighing as The Dependent Variable in Males

Kakuma et al
J Endocrinol Metab. 2020;10(1):8-15

13

Self-Weighing in Japanese Medical Students
evaluate whether minimal weight changes lead to an increaseor decrease in self-weighing habits in college students who aremostly normal-weight individuals.
Our previous study demonstrated that daily self-weighing
contributes to favorable glycemic control independent of prospective weight loss [7]. However, the relationship between
habitual self-weighing and glucose metabolism was not observed in the present study. There are some possible reasonsfor the difference in results between the studies of working
adults and college students. First, the students in the present
study were not as old as subjects enrolled in previous studies.
There is an essential difference in glucose tolerance between
late middle-aged subjects and young postadolescent subjects.
This may be one of the reasons that glucose metabolism ofstudents with daily self-weighing habits was not different fromthat of students without daily self-weighing habits. The otherexplanation is associated with the difference between patientswith type 2 diabetes and generally healthy students. Therefore,
the benefit of self-weighing might not be observed in the students whose IGT was only 4.3%.
A recent longitudinal observational study of persons witha mean age of 24 years showed that only a quarter of young
adults maintained their body weight over 10 years, 68.3% ofparticipants gained more than 5% of their weight and eating
regularly and having no history of excessive dieting (intentionally losing ≥ 5 kg) were significant factors related to successful weight maintenance in both genders [16]. This meansthat continuous regular eating habits are even more essential
to successful weight management. In the present study, skipping breakfast was independently and significantly related todaily self-weighing habits in males. The logistic regression
analysis suggests that not skipping breakfast may be a potent
factor for making daily self-weighing a lifelong habit in males.
If breakfast is not eaten, blood glucose levels will rise after
lunch, which is referred to as the second-meal phenomenon[17]. Thus, regularly eating breakfast is important for maintaining favorable glucose metabolism from a standpoint ofchrononutrition. Because of the cross-sectional study design,
it is impossible to determine a cause-and-effect relationshipbetween self-weighing and not skipping breakfast. However,
it is possible that regularly eating breakfast synergistically activated a healthy lifestyle by promoting daily self-weighing.
The ratio of college students who exercise regularly, eat late
at night and consume soft drinks is generally higher in males
than in females [8]. These tendencies were confirmed in ourstudy. Primarily, the reason the ratio of college students who
eat late dinners and consume excessive soft drinks was higher
in males may be because a higher number of males participated in athletic club activities or regularly exercised. In termsof healthy behaviors, exercise was more common in males,
whereas good eating habits and not smoking were more common in females. It is interesting that regular exercise was independently and significantly related to daily self-weighing
in females. In the present study, females more commonly
tended not to eat late at night or drink excessive amounts ofsoft drink, which suggests they placed more importance on
eating behaviors rather than exercise. Therefore, regular exercise may increase the motivation for self-weighing in females.
As mentioned above, habitual self-weighing accompanied by
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J Endocrinol Metab. 2020;10(1):8-15
regularly eating breakfast and exercising would synergistically be expected to prevent the pathogenesis of lifestyle-relateddiseases related to obesity, including type 2 diabetes, in college students.
There are several limitations to this study. Height andweight were self-reported to avoid measuring body weight infront of everyone, which was especially important for the female students. A recent study of 50 female students (mean age= 21 years) in Japan demonstrated that self-reported height andweight were reliable because intraclass correlation coefficients
between self-reported height and weight and those measured
with scales were above 0.9 [18]. However, to check the accuracy of our study, we compared self-reported height and weightto those measured with scales in routine physical exams at ouruniversity. Although the participants, especially females, may
underreport their measurements, there were no statistically significant differences between the self-reported data and healthexamination data (males vs. females: 171.3 (167.6 - 175.4) vs.
159.4 (155.3 - 162.8) in height; P < 0.001; 64.9 (59.7 - 70.8)
vs. 51.5 (47.9 - 55.1) in weight; P < 0.001), indicating that the
self-reported data did not influence the results of this study.
We cannot deny the possibility that the weights of participantschanged from the time of the routine exam in spring. In any
case, further observational studies with a larger sample size
are necessary to confirm these results. Some studies showedthat frequent self-weighing caused an increase in anxiety anddepression in younger females and predicted binge eating andunhealthy weight control behavior [13, 19]. Because questionnaires regarding unhealthy behaviors such as binge eating andfamily history of diabetes were not administered to students inthe present study, further studies should be conducted to examine ways to refine such types of interventions to improvetheir efficacy.
In conclusion, a habit of regular self-weighing may be anindicator of healthy individuals. Male students who skippedbreakfast and the female students who had a sedentary lifestyle
were less likely to perform habitual self-weighing. Self-weighing is a simple technique that can be used not only for weightloss in individuals who are overweight or obese but also forweight maintenance in normal-weight populations. Weight
monitoring provides an opportunity for positive feedback forstudents to identify how specific situations or patterns of eatingor physical activity relate to changes in body weight. Eating
breakfast for males and exercising regularly for females, alongwith habitual self-weighing, may synergistically help establish
a healthy lifestyle.

Acknowledgments
We thank Keishi Mori for his assistance with the statisticalanalysis.

Financial DisclosureThis research did not receive any specific grant from funding
agencies in the public, commercial, or not-for-profit sectors.

Articles © The authors | Journal compilation © J Endocrinol Metab and Elmer Press Inc™ | www.jofem.org

Kakuma et al

J Endocrinol Metab. 2020;10(1):8-15

Conflict of Interest

6.

The authors declare that there are no conflict of interest.
7.

Informed Consent
Informed consent for the OGTT and for collecting information concerning physique and lifestyle behaviors was obtained
from all students while in school. Because students have already graduated, we announced that the opportunity to opt out
was always available by providing the information on the website of our department. To date, there have been no inquiries.

8.

Author Contributions

10.

Tetsuya Kskuma contributed to conceptualization, methodology, software, formal analysis, investigation, writing originaldraft and visualization. Seiko Ariki and Yuichi Yoshida contributed to investigation and data curation. Hirotaka Shibata
contributed to supervision and project administration. Takashi
Tsutsumi and Yoshikuni Kudo contributed to writing review
and editing. All authors read and approved the final manuscript.

9.

11.

12.
13.

Data Availability
The data supporting the findings of this study are available
from the corresponding author upon reasonable request.

14.

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