Eileen Lividoti Hibert

Job strain and changes in the body mass index among working women: a prospective study.

Objective:The relationship between job strain and weight gain has been unclear, especially for women. Using data from over 52 000 working women, we compare the association between change in job strain and change in body mass index (BMI) across different levels of baseline BMI.Subjects/Methods:We used data from participants in the Nurses’ Health Study II (n=52 656, mean age=38.4 years), an ongoing prospective cohort study. Using linear regression, we modeled the change in BMI over 4 years as a function of the change in job strain, baseline BMI and the interaction between the two. Change in job strain was characterized in four categories combining baseline and follow-up levels as follows: consistently low strain (low at both points), decreased strain (high strain at baseline only), increased strain (high strain at follow-up only) and consistently high strain (high at both points). Age, race/ethnicity, pregnancy history, job types and health behaviors at baseline were controlled for in the model.Results:In adjusted models, women who reported high job strain at least once during the 4-year period had a greater increase in BMI (ΔBMI=0.06–0.12, P<0.05) compared with those who never reported high job strain. The association between the change in job strain exposure and the change in BMI depended on the baseline BMI level (P=0.015 for the interaction): the greater the baseline BMI, the greater the BMI gain associated with consistently high job strain. The BMI gain associated with increased or decreased job strain was uniform across the range of baseline BMI.Conclusions:Women with higher BMI may be more vulnerable to BMI gain when exposed to constant work stress. Future research focusing on mediating mechanisms between job strain and BMI change should explore the possibility of differential responses to job strain by initial BMI.

Gestational Age, Infant Birth Weight, and Subsequent Risk of Type 2 Diabetes in Mothers: Nurses’ Health Study II

Introduction Women with a history of gestational diabetes mellitus (GDM) are at higher risk of developing type 2 diabetes (T2DM); however, little is known about the association between other common pregnancy complications (eg, preterm birth, macrosomia) and T2DM risk. We examined the associations between first-pregnancy preterm, postterm birth, low birth weight, and macrosomia with subsequent risk of T2DM. Methods We conducted a prospective cohort study of Nurses’ Health Study II (NHSII) participants; 51,728 women in the study had a single live birth and complete pregnancy history. NHSII confirmed incident diabetes mellitus through supplemental questionnaires. Participants were followed from year of first birth until 2005. We defined gestational age as very preterm (20 to ≤32 weeks), moderate preterm (33 to ≤37 weeks), term (38 to ≤42 weeks), and postterm (≥43 weeks). We defined low birth weight as an infant born at term weighing less than 5.5 pounds, and we defined macrosomia as an infant born at term weighing 10 pounds or more. We used Cox proportional hazards models, adjusting for potential confounders. Results Women with a very preterm birth (2%) had an increased T2DM risk (adjusted hazard ratio, 1.34; 95% confidence interval [CI], 1.05–1.71). This increased risk emerged in the decade following pregnancy. Macrosomia (1.5%) was associated with a 1.61 increased T2DM risk, after adjusting for risk factors, including GDM (95% CI, 1.24–2.08). This association was apparent within the first 5 years after pregnancy. Moderate preterm and term low birth weight did not significantly increase the risk of T2DM over the 35-year follow-up time. Conclusion Women who experienced a very preterm birth or had an infant that weighed 10 pounds or more may benefit from lifestyle intervention to reduce T2DM risk. If replicated, these findings could lead to a reduced risk of T2DM through improved primary care for women experiencing a preterm birth or an infant of nonnormal birth weight.

Gestational age, infant birth weight, and subsequent risk of type 2 diabetes in mothers

Introduction Women with a history of gestational diabetes mellitus (GDM) are at higher risk of developing type 2 diabetes (T2DM); however, little is known about the association between other common pregnancy complications (eg, preterm birth, macrosomia) and T2DM risk. We examined the associations between first-pregnancy preterm, postterm birth, low birth weight, and macrosomia with subsequent risk of T2DM. Methods We conducted a prospective cohort study of Nurses’ Health Study II (NHSII) participants; 51,728 women in the study had a single live birth and complete pregnancy history. NHSII confirmed incident diabetes mellitus through supplemental questionnaires. Participants were followed from year of first birth until 2005. We defined gestational age as very preterm (20 to ≤32 weeks), moderate preterm (33 to ≤37 weeks), term (38 to ≤42 weeks), and postterm (≥43 weeks). We defined low birth weight as an infant born at term weighing less than 5.5 pounds, and we defined macrosomia as an infant born at term weighing 10 pounds or more. We used Cox proportional hazards models, adjusting for potential confounders. Results Women with a very preterm birth (2%) had an increased T2DM risk (adjusted hazard ratio, 1.34; 95% confidence interval [CI], 1.05–1.71). This increased risk emerged in the decade following pregnancy. Macrosomia (1.5%) was associated with a 1.61 increased T2DM risk, after adjusting for risk factors, including GDM (95% CI, 1.24–2.08). This association was apparent within the first 5 years after pregnancy. Moderate preterm and term low birth weight did not significantly increase the risk of T2DM over the 35-year follow-up time. Conclusion Women who experienced a very preterm birth or had an infant that weighed 10 pounds or more may benefit from lifestyle intervention to reduce T2DM risk. If replicated, these findings could lead to a reduced risk of T2DM through improved primary care for women experiencing a preterm birth or an infant of nonnormal birth weight.

Shift work, job strain and changes in the body mass index among women: a prospective study

Objectives The effects of job strain and shift work on weight gain have not been studied jointly. Cross-sectional and longitudinal studies on shift work and weight gain have reported different results. This study examines potential effect modification by job strain on the link between shift work and weight gain, and concurrent and delayed effects of shift work on weight gain. Methods Data came from 52 622 women who participated in the Nurses’ Health Study II, a prospective cohort study. Using linear regression, we modelled change in body mass index (BMI) over 4 years as a function of change in job strain, cumulative exposure to rotating night shift previously and during the 4 years (ie, previous and concurrent exposures) and the interaction between job strain and concurrent shift work exposure. Age, race/ethnicity, pregnancy history, baseline BMI, job types and health behaviours at baseline were controlled for. Results Job strain and rotating shift work, concurrent and previous, all had independent associations with BMI change during the 4-year period. There was no evidence for effect modification by job strain. Concurrent and previous exposures to rotating night shift had different associations with BMI change: an inverted U-shape for concurrent exposure (ranging from 0.01 to 0.14 kg/m2 increase), a dose–response for previous exposure (−0.02 to 0.09 kg/m2). Conclusions Job strain and rotating night shift work have independent contributions to weight gain. Reducing job strain and supporting night shift workers are both important intervention goals.

Peer Reviewed: Gestational Age, Infant Birth Weight, and Subsequent Risk of Type 2 Diabetes in Mothers: Nurses’ Health Study II

Introduction Women with a history of gestational diabetes mellitus (GDM) are at higher risk of developing type 2 diabetes (T2DM); however, little is known about the association between other common pregnancy complications (eg, preterm birth, macrosomia) and T2DM risk. We examined the associations between first-pregnancy preterm, postterm birth, low birth weight, and macrosomia with subsequent risk of T2DM. Methods We conducted a prospective cohort study of Nurses’ Health Study II (NHSII) participants; 51,728 women in the study had a single live birth and complete pregnancy history. NHSII confirmed incident diabetes mellitus through supplemental questionnaires. Participants were followed from year of first birth until 2005. We defined gestational age as very preterm (20 to ≤32 weeks), moderate preterm (33 to ≤37 weeks), term (38 to ≤42 weeks), and postterm (≥43 weeks). We defined low birth weight as an infant born at term weighing less than 5.5 pounds, and we defined macrosomia as an infant born at term weighing 10 pounds or more. We used Cox proportional hazards models, adjusting for potential confounders. Results Women with a very preterm birth (2%) had an increased T2DM risk (adjusted hazard ratio, 1.34; 95% confidence interval [CI], 1.05–1.71). This increased risk emerged in the decade following pregnancy. Macrosomia (1.5%) was associated with a 1.61 increased T2DM risk, after adjusting for risk factors, including GDM (95% CI, 1.24–2.08). This association was apparent within the first 5 years after pregnancy. Moderate preterm and term low birth weight did not significantly increase the risk of T2DM over the 35-year follow-up time. Conclusion Women who experienced a very preterm birth or had an infant that weighed 10 pounds or more may benefit from lifestyle intervention to reduce T2DM risk. If replicated, these findings could lead to a reduced risk of T2DM through improved primary care for women experiencing a preterm birth or an infant of nonnormal birth weight.