Exploring the Factors Contributing to Sibling Correlations in BMI: A Study Using the Panel Study of Income Dynamics

Abstract

Understanding the mechanisms contributing to correlated BMI outcomes in a social network such as siblings will help policy makers reduce the burden of disease associated with obesity. There are two potential mechanisms explaining correlated BMI outcomes in a biologically related social network: (i) time constant factors such as genetic heritability and habits formed during childhood and (ii) factors that change over time some of which are dependent on the frequency of interactions between the social network, for example, social norms shaped by the social network's shifting attitudes towards weight and behaviors related to weight, or environmental factors like opportunities for exercise. This study aims to distinguish between time constant factors from factors that are likely to change over time to gain a better understanding of the mechanisms explaining the correlation in sibling BMI. We exploit data from the Panel Study of Income Dynamics (PSID) over 1999–2007 estimating the correlation in BMI for adult siblings who currently live in separate households but grew-up in the same household and adolescent siblings currently living in the same household to isolate the influence of factors that change over time. The findings indicate that time constant factors explain some of the overall correlation in sibling BMI for both cohorts of siblings. Factors that change over time only significantly impact on the overall correlation in BMI for adolescent siblings suggesting if there is a social network influence on correlations in BMI this is facilitated by sharing the same household.

Familial correlation and aggregation of body mass index and blood pressure in Chinese Han population

“…Previous studies have shown the greatest absolute BMI increase was within the already heaviest population [33], and only a moderate amount of SBP and DBP is accounted for by genetic factors [34], indicating the unignorable large impact of shared environment. Recently, Brown et al further added that, based on a US sibling cohort, sharing the same household could facilitate the social network influence on correlations in BMI [35]. Meanwhile, in our study, despite relatively low BMI, SBP and DBP levels in rural areas and low income families, statistically significant ICCs of overweight/obesity (BMI ≥ 25 kg/m 2 ) were only shown in rural areas, and those of high BP (SBP ≥ 120 mmHg or DBP ≥ 80 mmHg) were presented in low-income families and in regions of all modernization levels.…”

Poor Adherence to US Dietary Guidelines for Children and Adolescents in the National Health and Nutrition Examination Survey Population

“…1-3 Growing evidence that dietary habits developed during childhood often persist into adulthood both raises concern and creates opportunity for intervention because poor dietary quality is recognized as a risk factor for chronic diseases among adults including diabetes, cardiovascular disease, and cancer. 4,5 However, we know relatively little about differences in the dietary quality of children at different ages in the developed world. Several indices exist to measure dietary quality and, although small differences exist, all focus on adherence to a diet that emphasizes vegetables, fruits, whole grains, low-fat dairy, fish, and unsaturated fatty acids.…”

Current Trends in Childhood Obesity Research

“…Brown and Roberts [24] found that, among adolescents, timeconstant factors (i.e., genetics, individual characteristics, home environments) and time-changing factors (i.e., social network influences) explained 43 % and 44 %, respectively, of weight correlations across statistical models. Among adult-sibling models, the contribution of time-constant factors remained relatively high (33-38 %), but time-changing factors explained less variation (5-15 %).…”