Predictors of Hemoglobin A1c Among Adults 40 to 59 Years of Age in the United States
Authors:   , Nicolo Michele , Volpe Stella L. 
Published: July 2021

Objective: The risk for type 2 DM increases with age, becoming more significant after 45 years of age. The present research is intended to expand upon the current literature by investigating whether dietary magnesium intake, indirect measures of body composition (Body Mass inDex (BMI), waist circumference, waist-to-height ratio) and sedentary behavior activity are predictive of hemoglobin A1c percentage. Research Design and Methods: We used cross-sectional data, including adults 40 to 59 years of age, from the National Health and Nutrition Examination Survey (NHANES) for 2003 to 2004 and 2013 to 2014. Responses to survey questions for dietary intake, anthropometric measurements (BMI, waist circumference, and waist-to-height ratio), and responses to the Physical Activity Questionnaire regarding time watching television or videos, and time spent sitting in front of a computer per day were analyzed. A binary logistic regression analysis was used to determine whether dietary magnesium, BMI, wait circumference, waist-to-height ratio or sedentary behavior time were predictors of a HbA1c [greater than or equal to] 6.5%. The regression model was further adjusted for age, sex, race and ethnicity. Results: Using a univariate binary logistic regression analyses, the odds of having a HbA1c measure of [greater than or equal to] 6.5% was not associated with mean dietary magnesium intake (NHANES 2003 to 2004 [p=0.873]; NHANES 2013 to 2014 [p=0.534]). Adding age, sex, race and ethnicity into the model, the odds of having a HbA1c of [greater than or equal to] 6.5% were not associated with mean dietary magnesium intake (NHANES 2003 to 2004 [p=0.310]; NHANES 2013 to 2014, [p=0.530]). Measures of BMI, waist circumference and waist-to-height ratio were lower between NHANES 2003 to 2004 and NHANES 2013 to 2014 (p=0.0001). The odds of having a HbA1c measure of [greater than or equal to] 6.5% was significantly associated with having a greater BMI, waist circumference and waist-to-height ratio (p=0.0001). In the 2003 to 2004 NHANES sample multivariate model only, waist-to-height ratio was associated with greater odds of having a measured HbA1c of [greater than or equal to] 6.5% (OR: 2.91, 95% CI: 1.69, 5.04). In a univariate model, adults reporting [greater than or equal to] 8 hours of SBT in NHANES 2003 to 2004 had 2.02 increased odds of a HbA1c [greater than or equal to] 6.5% (OR= 2.02, 95% CI: 1.31, 3.13, p<0.0001) compared to adults reporting [less than or equal to] 3 hours. After adjusting the regression model for age, sex, race, ethnicity and body mass index, adults reporting [greater than or equal to] 8 hours of SBT in NHANES 2003 to 2004 had 1.72 increased odds of HbA1c [greater than or equal to] 6.5% (OR= 2.02, 95% CI: 1.10, 2.68, p<0.0001) compared to adults reporting [less than or equal to] 3 hours of SBT. Reported SBT was not a predictor of HbA1c [greater than or equal to] 6.5% for NHANES 2013 to 2014. Conclusion: Dietary magnesium was not a predictor of HbA1c [greater than or equal to] 6.5% among adults, 40 to 59 years of age, in NHANES 2003 to 2004 and 2013 to 2014. Waist circumference and waist-to-height ratio were predictors of HbA1c [greater than or equal to] 6.5% among adults, 40 to 59 years of age, in NHANES 2003 to 2004 but not in NHANES 2013 to 2014. SBT was a predictor of HbA1c [greater than or equal to] 6.5% among adults, 40 to 59 years of age, in NHANES 2003 to 2004, but was not a predictor in NHANES 2013 to 2014.