Investigating nutrition and lifestyle factors as determinants of abdominal obesity: an environment-wide study

BACKGROUND: The increasing global trends in obesity and its associated burden of disease indicate a need to identify modifiable determinants of obesity. METHODS: A total of 182 nutrition and lifestyles factors were investigated in relation to abdominal obesity among 7,403 male and 8,328 female participants of the Third U.S. National Health and Examination Survey (NHANES III). We used the first phase (1988-1991) of the NHANES III to identify factors with a false discovery rate (FDR) of <5%. Of these, we tentatively replicated our findings in the second phase (1992-1994) of the survey. Principal component analysis was performed to identify unobserved factors underlying the association between validated factors and abdominal obesity, defined as waist circumference 488 cm for women and >102 cm for men. RESULTS: We found five tentatively replicated factors showing significant associations with abdominal obesity in men: serum alpha-carotene, beta-carotene, serum beta-cryptoxanthin, serum vitamin D and vigorous physical activity. In women, 7 factors were identified: serum alpha-carotene, beta-carotene, serum beta-cryptoxanthin, serum vitamin C, serum vitamin D, vigorous physical activity and aspartame intake. In contrast to the other factors which showed inverse associations with abdominal obesity, aspartame intake displayed a positive relationship with this outcome (OR: 1.18, 95% CI: 1.10-1.26 for each log increase in aspartame intake in women). Principal component analysis suggested three principal components underlying such associations, each comprising: (1) serum antioxidants; (2) serum vitamin D and vigorous physical activity; and (3) aspartame intake. All three principal components also displayed significant associations with abdominal obesity. CONCLUSION: Our observational investigation that systematically investigates multiple modifiable factors simultaneously has enabled the creation of data-driven hypotheses regarding the possible role of determinants of abdominal obesity and has identified potential avenues for mechanistic investigations to clarify suitable targets of intervention.