RESUMEN
OBJECTIVE: The Old Order Amish (OOA) is a conservative Christian sect of European origin living in Pennsylvania. Diabetes is rare in adult OOA despite a mean BMI rivaling that in the general U.S. non-Hispanic white population. The current study examines childhood factors that may contribute to the low prevalence of diabetes in the OOA by comparing OOA children aged 8-19 years with National Health and Nutrition Examination Survey (NHANES) data and children from Maryland's Eastern Shore (ES), a nearby, non-Amish, rural community. We hypothesized that pediatric overweight is less common in OOA children, that physical activity (PA) and BMI are inversely correlated, and that OOA children are more physically active than ES children. RESEARCH DESIGN AND METHODS: We obtained anthropometric data in 270 OOA children and 229 ES children (166 non-Hispanic white, 60 non-Hispanic black, 3 Hispanic). PA was measured by hip-worn accelerometers in all ES children and in 198 OOA children. Instrumentation in 43 OOA children was identical to ES children. RESULTS: OOA children were approximately 3.3 times less likely than non-Hispanic white ES children and NHANES estimates to be overweight (BMI ≥85th percentile, Centers for Disease Control and Prevention). Time spent in moderate/vigorous PA (MVPA) was inversely correlated to BMI z-score (r = -0.24, P = 0.0006). PA levels did not differ by ethnicity within the ES group, but OOA children spent an additional 34 min/day in light activity (442 ± 56 vs. 408 ± 75, P = 0.005) and, impressively, an additional 53 min/day in MVPA (106 ± 54 vs. 53 ± 32, P < 0.0001) compared with ES children. In both groups, boys were more active than girls but OOA girls were easily more active than ES boys. CONCLUSIONS: We confirmed all three hypotheses. Together with our previous data, the study implies that the OOA tend to gain their excess weight relatively late in life and that OOA children are very physically active, both of which may provide some long-term protection against diabetes.
Asunto(s)
Actividad Motora/fisiología , Adolescente , Adulto , Factores de Edad , Amish/estadística & datos numéricos , Antropometría , Índice de Masa Corporal , Niño , Ejercicio Físico/fisiología , Femenino , Humanos , Masculino , Encuestas Nutricionales , Obesidad/epidemiología , Sobrepeso/epidemiología , Pennsylvania , Prevalencia , Factores Sexuales , Adulto JovenRESUMEN
BACKGROUND: Common FTO (fat mass and obesity associated) gene variants have recently been associated with body mass index (BMI) and obesity in several large studies. The role of lifestyle factors (such as physical activity) in those with an underlying FTO genetic predisposition is unknown. METHODS: To determine if FTO variants are associated with BMI in Old Order Amish (OOA) individuals, and to further determine whether the detrimental associations of FTO gene variants can be lessened by increased physical activity, a total of 704 healthy OOA adults were selected from the Heredity and Phenotype Intervention (HAPI) Heart Study, an investigation of gene x environment interactions in cardiovascular disease, for whom objective quantified physical activity measurements were available and for whom 92 single-nucleotide polymorphisms (SNPs) in FTO were genotyped. RESULTS: Twenty-six FTO SNPs were associated with BMI (P = .04 to <.001), including rs1477196 (P < .001) and rs1861868 (P < .001), 2 SNPs in moderate linkage disequilibrium in the OOA (D' = 0.82; r(2) = 0.36). Stratified analyses of rs1861868 revealed its association with BMI to be restricted entirely to those subjects with low sex- and age-adjusted physical activity scores (P < .001); in contrast, the SNP had no effect on those with above-average physical activity scores (P = .29), with the genotype x physical activity interaction achieving statistical significance (P = .01). Similar evidence for interaction was also obtained for rs1477196. CONCLUSIONS: Our results strongly suggest that the increased risk of obesity owing to genetic susceptibility by FTO variants can be blunted through physical activity. These findings emphasize the important role of physical activity in public health efforts to combat obesity, particularly in genetically susceptible individuals.