A within-sibling pair analysis of lifestyle behaviours and BMI z-score in the multi-centre I.Family study

Abstract

Background and aims: By investigating differences in lifestyle behaviours and BMI in sibling pairs, family-level confounding is minimized and causal inference is improved, compared to cross-sectional studies of unrelated children. Thus, we aimed to investigate within-sibling pair differences in different lifestyle behaviours and differences in BMI z-scores in children and adolescents. Methods and results: We examined three groups of sibling pairs 1) all same-sex sibling pairs with maximum 4 years age difference (n Z 1209 pairs from 1072 families in 8 countries, mean age 10.7 years, standard deviation 2.4 years), 2) sibling pairs discordant for overweight (n Z 262) and 3) twin pairs (n Z 85). Usual dietary intake was estimated by 24-h recalls and time spent in light (LPA) and moderate-to-vigorous physical activity (MVPA) was measured by accelerometers. Screen time, sleep and dieting for weight loss were assessed by questionnaires.Within all 3 groups of sibling pairs, more time in MVPA was associated with lower BMI z-score. Higher energy intake was associated with higher BMI z-score within twin pairs and within all Abbreviations: 24HDR 24-hour dietary recall, BMI Body mass index; IOTF International Obesity Task Force, ISCOLE International Study of Childhood Obesity; Lifestyle and the Environment, MVPA Moderate-to-vigorous physical activity; PA Physical activity, SACANA Self-

Weight discordant siblings’ ability to reduce energy intake at a meal as compensation for prior energy intake from sugar-sweetened beverages (SSBs)

“…One is that ability to compensate for energy in SSBs contributes minimally to siblings’ differences in adiposity. Other factors, such as differences in dietary restraint (Table 5) and physical activity (Roemmich et al, 2010; Bogl et al, 2019) appear to have a greater impact upon sibling differences in body weight. Another possibility is that differences in compensation ability will eventually lead to differences in adiposity but that these differences were not apparent in such a short duration study.…”

A Cross-Sectional Study on the Relationship between the Family Nutrition Climate and Children’s Nutrition Behavior

“…Other research already showed that family members influence each other’s nutrition behaviors. For example, families have similar dietary intakes [26,27], especially regarding the consumption of healthy nutrition [26]. Our study specifically shows the influence of shared values, routines, and interaction patterns concerning healthy nutrition within a family (defined as the family nutrition climate) on the child’s nutrition behavior.…”

Obesity and eating behavior from the perspective of twin and genetic research

“…The logic of extended pedigree studies is to collect information on relatives having different genetic and environmental relatedness, thus allowing for estimation of genetic and environmental variation. However, in some cases even just collecting information on nuclear families is enough if the interest is only to take into account the total familial effect combining genetic factors and shared environment (Bogl et al, 2019). The history of family studies on BMI goes back to the early 20 th century when it was first shown that obesity clusters in families, indicating the importance of genetic factors (Davenport, 1923).…”