Breastfeeding duration and weight gain trajectory in infancy.

BACKGROUND AND OBJECTIVES: Short breastfeeding duration may exacerbate accelerated early growth, which is linked to higher obesity risk in later life. This study tested the hypothesis that infants at higher risk for obesity were more likely to be members of a rising weight-for-length (WFL) z score trajectory if breastfed for shorter durations. METHODS: This prospective, observational study recruited women from an obstetric patient population in rural central New York. Medical records of children born to women in the cohort were audited for weight and length measurements (n = 595). We identified weight gain trajectories for infants' WFL z scores from 0 to 24 months by using maximum likelihood latent class models. Individual risk factors associated with weight gain trajectories (P ≤ .05) were included in an obesity risk index. Logistic regression analysis was performed to investigate whether the association between breastfeeding duration (<2 months, 2-4 months, >4 months) and weight gain trajectory varied across obesity risk groups. RESULTS: Rising and stable weight gain trajectories emerged. The obesity risk index included maternal BMI, education, and smoking during pregnancy. High-risk infants breastfed for <2 months were more likely to belong to a rising rather than stable weight gain trajectory (odds ratio, 2.55; 95% confidence interval, 1.14-5.72; P = .02). CONCLUSIONS: Infants at the highest risk for rising weight patterns appear to benefit the most from longer breastfeeding duration. Targeting mothers of high-risk infants for breastfeeding promotion and support may be protective against overweight and obesity during a critical window of development.

Associations Between Mothers' and Their Children's Weights at 4 Years of Age.

OBJECTIVES: To examine the importance of maternal weight characteristics as predictors of overweight (BMI ≥85th percentile and <95th percentile) and obesity (BMI ≥ 95th percentile) in offspring at age 4 years. METHODS: Chi-square and logistic regression analyses were conducted on a sample of 321 mother/child pairs from an earlier observational cohort study on mothers' postpartum weight retention. RESULTS: Maternal early pregnancy BMI and infant birth weight were each positively and significantly (p <0.05) associated with increased risk of obesity in offspring at age 4 years. A significant interaction was found between these two variables in predicting children's risk of obesity. It was driven by the high proportion of obese children among obese women who had infants weighing < 3 kg at birth. Net gestational weight gain was not associated with obesity risk in children, but was positively associated with infant birth weight among normal weight and overweight women. CONCLUSIONS: Reducing maternal BMI in the preconception period among overweight and obese women and preventing excessive weight gain in pregnancy for all women appear to be appropriate strategies to address the childhood obesity epidemic.

Cellular localization and function of the antiviral protein, ovine Mx1 (oMx1): I. Ovine Mx1 is secreted by endometrial epithelial cells via an 'unconventional' secretory pathway.

PROBLEM: Embryonic loss is a major contributor to infertility. Understanding factors contributing to embryonic loss will aid in development of technologies to improve/regulate fertility in animals and humans. METHOD OF STUDY: We tested the hypothesis that the antiviral protein, ovine Mx1 (oMx1), is secreted by uterine epithelial cells. Uterine flushes were obtained from cyclic and early pregnant ewes and examined for levels of oMx1 protein. The pathway for ovine Mx1 secretion in ovine glandular epithelial (oGE) cells was determined using brefeldin A (BFA), an inhibitor of the conventional secretory pathway. Effects of BFA were determined using beta2-microglobulin (beta2MG) as a marker for the conventional secretory pathway, and interferon stimulated gene 15 (ISG15) and Galectin-1 (Gal-1) as markers for the unconventional secretory pathways. RESULTS: Ovine Mx1 protein levels were low in uterine flushes from cyclic ewes and levels increased in pregnant ewes after D 15. Ovine GE cells secreted oMx1 in response to interferon and secretion was not reduced by BFA, suggesting oMx1 was secreted via an unconventional secretory pathway. beta2MG secretion was reduced by BFA, whereas ISG15 and Gal-1 were not. CONCLUSION: This is the first report that the antiviral protein, oMx1, is secreted and provides evidence that secretion occurs via unconventional secretory pathway(s).