The timing of associations between common genetic variants for weight or body mass index (BMI) across the life course may provide insights into the aetiology of obesity. We genotyped variants in FTO (rs9939609) and near MC4R (rs17782313) in 1240 men and 1239 women born in 1946 and participating in the MRC National Survey of Health and Development. Birth weight was recorded and height and weight were measured or self-reported repeatedly at 11 time-points between ages 2 and 53 years. Hierarchical mixed models were used to test whether genetic associations with weight or BMI standard deviation scores (SDS) changed with age during childhood and adolescence (2–20 years) or adulthood (20–53 years). The association between FTO rs9939609 and BMI SDS strengthened during childhood and adolescence (rate of change: 0.007 SDS/A-allele/year; 95% CI: 0.003–0.010, P < 0.001), reached a peak strength at age 20 years (0.13 SDS/A-allele, 0.08–0.19), and then weakened during adulthood (−0.003 SDS/A-allele/year, −0.005 to −0.001, P = 0.001). MC4R rs17782313 showed stronger associations with weight than BMI; its association with weight strengthened during childhood and adolescence (0.005 SDS/C-allele/year; 0.001–0.008, P = 0.006), peaked at age 20 years (0.13 SDS/C-allele, 0.07–0.18), and weakened during adulthood (−0.002 SDS/C-allele/year, −0.004 to 0.000, P = 0.05). In conclusion, genetic variants in FTO and MC4R showed similar biphasic changes in their associations with BMI and weight, respectively, strengthening during childhood up to age 20 years and then weakening with increasing adult age. Studies of the aetiology of obesity spanning different age groups may identify age-specific determinants of weight gain.

BackgroundStrategies to optimize early-life nutrition provide an important opportunity for primary prevention of childhood obesity. Interventions that can be efficiently scaled-up to the magnitude needed for sustainable childhood obesity prevention are needed. The objective of this study was to evaluate the effects of an eHealth intervention on parental feeding practices and infant eating behaviors.MethodsThe Norwegian study Early Food for Future Health is a randomized controlled trial. Parents were recruited via social media and child health clinics during spring 2016 when their child was aged 3 to 5 months. In total 718 parents completed a web-based baseline questionnaire at child age 5.5 months. The intervention group had access to a webpage with monthly short video clips addressing specific infant feeding topics and age-appropriate baby food recipes from child age 6 to 12 months. The control group received routine care. The primary outcomes were child eating behaviors, dietary intake, mealtime routines and maternal feeding practices and feeding styles. The secondary outcomes were child anthropometry. This paper reports outcomes at child age 12 months.ResultsMore than 80% of the intervention group reported viewing all/most of the video clips addressing infant feeding topics and indicated that the films were well adapted to the child’s age and easy to understand. Children in the intervention group were served vegetables/fruits more frequently (p = 0.035) and had tasted a wider variety of vegetables (p = 0.015) compared to controls. They were also more likely to eat family breakfast (p = 0.035) and dinner (p = 0.011) and less likely to be playing or watching TV/tablet during meals (p = 0.009) compared to control-group children. We found no group differences for child anthropometry or maternal feeding practices.ConclusionsOur findings suggest that the eHealth intervention is an appropriate and feasible tool to propagate information on healthy infant feeding to Norwegian mothers. Our study also suggests that anticipatory guidance on early protective feeding practices by such a tool may increase young children’s daily vegetable/fruit intake and promote beneficial mealtime routines.Trial registrationISRCTN, ISRCTN13601567. Registered 29 February 2016, http://www.isrctn.com/ISRCTN13601567Electronic supplementary materialThe online version of this article (10.1186/s12966-018-0763-4) contains supplementary material, which is available to authorized users.

Aim-To test the hypothesis that low plasma vitamin B12 concentrations combined with high folate concentrations in pregnancy are associated with higher incidence of gestational diabetes (GDM) and later diabetes.Methods-Women (N=785) attending the antenatal clinics of the Holdsworth Memorial Hospital, Mysore, India had their anthropometry, insulin resistance (Homeostasis Model Assessment) and glucose tolerance assessed at 30 weeks gestation (100g Oral Glucose Tolerance Test/ OGTT; Carpenter-Coustan criteria), and five years after delivery (75g OGTT, WHO 1999). Vitamin B12 and folate concentrations in pregnancy were measured in stored frozen plasma samples.Results-Low vitamin B12 concentrations (<150 pmol/l, B12 deficiency) were observed in 43% of women and low folate concentrations (<7 nmol/l) in 4%. Women with vitamin B12 deficiency had higher body mass index (BMI; P<0.001), sum of skinfolds (P<0.001), insulin resistance (P=0.02) and a higher incidence of GDM (8.7% v 4.6%; OR=2.14, P=0.02; P=0.1 after adjusting for maternal BMI) than non-deficient women. Among vitamin B12-deficient women the incidence of GDM increased with folate concentration (5.6%, 8.8%, 12.8% respectively from lowest to highest third; P for interaction=0.2). B12 deficiency during pregnancy predicted larger skinfolds, increased insulin resistance (P<0.05) and incident diabetes at 5-year follow-up (P=0.02, after adjusting for current BMI).Conclusion-Maternal vitamin B12 deficiency is associated with increased adiposity and, in turn, with increased insulin resistance and GDM, especially in the presence of high folate concentrations. Vitamin B12 deficiency may be an important factor underlying the high risk of diabesity in south Asian Indians.