Sagittal Abdominal Diameter and its Socioeconomic Correlates: Perspective of Sex Differences

Abstract Background Sagittal abdominal diameter (SAD) is an anthropometric measure of visceral adiposity. It remains unclear whether SAD and its socio-economic correlates differ in women and men, which limits the epidemiological and clinical applications of the SAD measurement. Methods A complex stratified multistage clustered sampling design was used to select 6,975 men and 7,079 women aged 18 years or more from the National Health Nutrition and Examination Survey 2011-2016, representative of the US civilian non-institutionalized population. SAD was measured in accordance to the standard protocols using a two-arm abdominal caliper. The sex differences in SAD and its socio-economic correlates were evaluated by performing weighted independent t tests and weighted multiple regression. Results SAD was lower in women than in men in the entire sample, as well as in all subgroups characterized by age, race, body mass index, birth place, and household income except for non-Hispanic blacks and those with household income < $20,000. Adjusted for other characteristics, SAD increased with age and body mass index for both women and men (p<.0001). Compared to white women, Asian women were associated with lower SAD (p=.018), and black women with higher SAD (p<.0001). Compared to white men, Hispanic and Asian men were associated with lower SAD (both p<.0001). Women born in other countries were more likely to have lower SAD than women born in the US (p<.0001), and so were men (p=.0118). Both women and men with a household income of <$75,000 had higher SAD than those with an income of over $75,000.Conclusion Women have lower SAD than men in the general population as well as in the most socio-economic subgroups. Socio-economic correlates of SAD were consistent in women and men.