Improving adherence to healthy dietary patterns, genetic risk, and long term weight gain: gene-diet interaction analysis in two prospective cohort studies

Objective To investigate whether improving adherence to healthy dietary patterns interacts with the genetic predisposition to obesity in relation to long term changes in body mass index and body weight.

Design Prospective cohort study.

Setting Health professionals in the United States.

Participants 8828 women from the Nurses’ Health Study and 5218 men from the Health Professionals Follow-up Study.

Exposure Genetic predisposition score was calculated on the basis of 77 variants associated with body mass index. Dietary patterns were assessed by the Alternate Healthy Eating Index 2010 (AHEI-2010), Dietary Approach to Stop Hypertension (DASH), and Alternate Mediterranean Diet (AMED).

Main outcome measures Five repeated measurements of four year changes in body mass index and body weight over follow-up (1986 to 2006).

Results During a 20 year follow-up, genetic association with change in body mass index was significantly attenuated with increasing adherence to the AHEI-2010 in the Nurses’ Health Study (P=0.001 for interaction) and Health Professionals Follow-up Study (P=0.005 for interaction). In the combined cohorts, four year changes in body mass index per 10 risk allele increment were 0.07 (SE 0.02) among participants with decreased AHEI-2010 score and −0.01 (0.02) among those with increased AHEI-2010 score, corresponding to 0.16 (0.05) kg versus −0.02 (0.05) kg weight change every four years (P<0.001 for interaction). Viewed differently, changes in body mass index per 1 SD increment of AHEI-2010 score were −0.12 (0.01), −0.14 (0.01), and −0.18 (0.01) (weight change: −0.35 (0.03), −0.36 (0.04), and −0.50 (0.04) kg) among participants with low, intermediate, and high genetic risk, respectively. Similar interaction was also found for DASH but not for AMED.

Conclusions These data indicate that improving adherence to healthy dietary patterns could attenuate the genetic association with weight gain. Moreover, the beneficial effect of improved diet quality on weight management was particularly pronounced in people at high genetic risk for obesity.

Reference: BMJ 2018;360:j5644

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Associations of Weight Gain From Early to Middle Adulthood With Major Health Outcomes Later in Life

Question  What is the association of weight gain from early to middle adulthood with health outcomes later in life?

Findings  During a follow-up of 18 years in 92 837 US women and 15 years in 25 303 US men, compared with participants who maintained a stable weight (weight loss ≤2.5 kg or gain <2.5 kg), those who gained a moderate amount of weight (≥2.5-<10.0 kg) had increased incidence of type 2 diabetes (absolute rate difference/100 000 person-years of 98 in women and 111 in men), cardiovascular disease (61 in women), obesity-related cancer (37 in women and 42 in men), and mortality (51 among women who never smoked).

Meaning  Among women and men, moderate weight gain from early to middle adulthood was associated with significantly increased risk of major chronic diseases and mortality.

Reference: JAMA. 2017;318(3):255-269.

Antibiotic Exposure During the First 6 Months of Life and Weight Gain During Childhood

Importance  Early-life antibiotic exposure has been associated with increased adiposity in animal models, mediated through the gut microbiome. Infant antibiotic exposure is common and often inappropriate. Studies of the association between infant antibiotics and childhood weight gain have reported inconsistent results.

Objective  To assess the association between early-life antibiotic exposure and childhood weight gain.

Design and Setting  Retrospective, longitudinal study of singleton births and matched longitudinal study of twin pairs conducted in a network of 30 pediatric primary care practices serving more than 200 000 children of diverse racial and socioeconomic backgrounds across Pennsylvania, New Jersey, and Delaware.

Participants  Children born between November 1, 2001, and December 31, 2011, at 35 weeks’ gestational age or older, with birth weight of 2000 g or more and in the fifth percentile or higher for gestational age, and who had a preventive health visit within 14 days of life and at least 2 additional visits in the first year of life. Children with complex chronic conditions and those who received long-term antibiotics or multiple systemic corticosteroid prescriptions were excluded. We included 38 522 singleton children and 92 twins (46 matched pairs) discordant in antibiotic exposure. Final date of follow-up was December 31, 2012.

Exposure  Systemic antibiotic use in the first 6 months of life.

Main Outcomes and Measures  Weight, measured at preventive health visits from age 6 months through 7 years.

Results  Of 38 522 singleton children (50% female; mean birth weight, 3.4 kg), 5287 (14%) were exposed to antibiotics during the first 6 months of life (at a mean age of 4.3 months). Antibiotic exposure was not significantly associated with rate of weight change (0.7%; 95% CI, −0.1% to 1.5%;P = .07, equivalent to approximately 0.05 kg; 95% CI, −0.004 to 0.11 kg of added weight gain between age 2 years and 5 years). Among 92 twins (38% female; mean birth weight, 2.8 kg), the 46 twins who were exposed to antibiotics during the first 6 months of life received them at a mean age of 4.5 months. Antibiotic exposure was not significantly associated with a weight difference (−0.09 kg; 95% CI, −0.26 to 0.08 kg; P = .30).

Conclusions and Relevance  Exposure to antibiotics within the first 6 months of life compared with no exposure was not associated with a statistically significant difference in weight gain through age 7 years. There are many reasons to limit antibiotic exposure in young, healthy children, but weight gain is likely not one of them.

By Jeffrey S Geber et al, JAMA. 2016;315(12):1258-1265