Healthful dietary patterns and long-term weight change among women with a history of gestational diabetes mellitus.

BACKGROUND/OBJECTIVE: Diet represents a key strategy for the prevention of obesity and type 2 diabetes among women with a history of gestational diabetes mellitus (GDM), although effective dietary patterns to prevent weight gain in the long term are largely unknown. We sought to evaluate whether improvement in overall diet quality is associated with less long-term weight gain among high-risk women with prior GDM. SUBJECTS/METHODS: Women with a history of GDM (N=3397) were followed from 1991 to 2011, or until diagnosis of type 2 diabetes or other chronic disease. Usual diet was assessed via food frequency questionnaire every 4 years from which we calculated the Alternative Healthy Eating Index (aHEI-2010), Alternate Mediterranean Diet (AMED) and Dietary Approaches to Stop Hypertension (DASH) dietary pattern scores. Weight, lifestyle and health-related outcomes were self-reported every 2 years. We estimated the change in dietary score with change in body weight using linear regression models adjusting for age, baseline body mass index (BMI), baseline and simultaneous change in physical activity and smoking status and other risk factors. RESULTS: Women were followed up to 20 years, gaining an average 1.9 kg (s.d.=7.0) per 4-year period. Women in the highest quintile (Q5) of diet change (most improvement in quality) gained significantly less weight per 4-year period than the lowest quintile (Q1; decrease in quality), independent of other risk factors (4-year weight change, aHEI-2010: Q5=1.30 kg vs Q1=3.27 kg; AMED: Q5=0.94 kg vs Q1=2.56 kg, DASH: Q5=0.64 kg vs Q1=2.75 kg). Significant effect modification by BMI (p-interactions <0.001) indicated a greater magnitude of weight change among women with a higher baseline BMI for all three patterns. CONCLUSIONS: Increased diet quality was associated with less weight gain, independent of other lifestyle factors. Post-partum recommendations on diet quality may provide one strategy to prevent long-term weight gain in this high-risk group.

A prospective cohort study of endometriosis and subsequent risk of infertility.

STUDY QUESTION: Is there a temporal relationship between endometriosis and infertility? SUMMARY ANSWER: Endometriosis is associated with a higher risk of subsequent infertility, but only among women age <35 years. WHAT IS KNOWN ALREADY: Endometriosis is the most commonly observed gynecologic pathology among infertile women undergoing laparoscopic examination. Whether endometriosis is a cause of infertility or an incidental discovery during the infertility examination is unknown. STUDY DESIGN, SIZE, DURATION: This study included data collected from 58 427 married premenopausal female nurses <40 years of age from 1989 to 2005, who are participants of the Nurses' Health Study II prospective cohort. PARTICIPANTS/MATERIALS, SETTING, METHODS: Our exposure was laparoscopically confirmed endometriosis. Multivariate Cox proportional hazards regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for infertility risk (defined as attempting to conceive for >12 months) among women with and without endometriosis. MAIN RESULTS AND THE ROLE OF CHANCE: We identified 4612 incident cases of infertility due to any cause over 362 219 person-years of follow-up. Compared with women without a history of endometriosis, women with endometriosis had an age-adjusted 2-fold increased risk of incident infertility (HR = 2.12, 95% CI = 1.76-2.56) that attenuated slightly after accounting for parity. The relationship with endometriosis was only observed among women <35 years of age (multivariate HR <35 years = 1.77, 95% CI = 1.46-2.14; multivariate HR 35-39 years = 1.20, 95% CI = 0.94-1.53; P-interaction = 0.008). Risk of primary versus secondary infertility was similar subsequent to endometriosis diagnosis. Among women with primary infertility, 50% became parous after the endometriosis diagnosis, and among all women with endometriosis, 83% were parous by age 40 years. LIMITATIONS, REASONS FOR CAUTION: We did not have information on participants' intentions to conceive, but by restricting the analytic population to married women we increased the likelihood that pregnancies were planned (and therefore infertility would be recognized). Women in our cohort with undiagnosed asymptomatic endometriosis will be misclassified as unexposed. However, the small proportion of these women are diluted among the >50 000 women accurately classified as endometriosis-free, minimizing the impact of exposure misclassification on the effect estimates. WIDER IMPLICATIONS OF THE FINDINGS: This study supports a temporal association between endometriosis and infertility risk. Our prospective analysis indicates a possible detection bias in previous studies, with our findings suggesting that the infertility risk posed by endometriosis is about half the estimates observed in cross-sectional analyses. STUDY FUNDING/COMPETING INTERESTS: This work was supported by the National Institutes of Health (grant numbers: UM1 CA176726, HD52473, HD57210, T32DK007703, T32HD060454, K01DK103720). We have no competing interests to declare.