Joanne H. Rizzo

Excessive Gestational Weight Gain and Postpartum Weight Retention Among Obese Women

OBJECTIVE: To evaluate the incremental effect of weight gain above that recommended for term pregnancy (15 pounds) on postpartum weight retention at 1 year among obese women. METHODS: In a retrospective cohort study, we identified 1,656 singleton gestations resulting in live births among obese women (body mass index at or above 30 kg/m2) between January 2000 and December 2005 in Kaiser Permanente Northwest. Pregnancy weight change (last available predelivery weight minus weight at pregnancy onset) was categorized as less than 0, 0–15, greater than 15 to 25, greater than 25 to 35, and greater than 35 pounds. Postpartum weight change (weight at 1 year postpartum minus weight at pregnancy onset) was defined as less than 0, 0–10, and greater than 10 pounds. RESULTS: Total gestational weight gain was –33.2 (weight loss) to +98.0 pounds (weight gain). Nearly three fourths gained greater than 15 pounds, and they were younger and weighed less at baseline than women who gained 15 pounds or less. Pregnancy-related weight change showed a significant relationship with postpartum weight change. For each pound gained during pregnancy, there was a 0.4-pound increase above baseline weight at 1 year postpartum. In adjusted logistic regression models, the risk of a postpartum weight greater than 10 pounds over baseline was twofold higher for women gaining greater than 15 to 25 pounds compared with women gaining 0–15 pounds (odds ratio [OR] 2.18, 95% confidence interval [CI] 1.54–3.10), fourfold higher for women gaining greater than 25 to 35 pounds (OR 3.91, 95% CI 2.75–5.56), and almost eightfold higher for women gaining greater than 35 pounds (OR 7.66, 95% CI 5.36–10.97). CONCLUSION: Incremental increases in gestational weight gain beyond the current recommendation for obese women substantially increase the risk of weight retention at 1 year postpartum. LEVEL OF EVIDENCE: II

Nulliparity and fracture risk in older women: the study of osteoporotic fractures.

Whether nulliparity increases fracture risk is unclear from prior studies, which are limited by small samples or lack of measured bone mineral density. No study has evaluated whether the effect of parity differs by skeletal site. We prospectively analyzed the relationship of parity to the risk of incident nontraumatic hip, spine, and wrist fractures in 9704 women aged 65 years or older participating in the Study of Osteoporotic Fractures to determine if parity reduces postmenopausal fracture risk, and if so, if this risk reduction is (1) greater at weight‐bearing skeletal sites and (2) independent of bone mineral density. Parity was ascertained by self‐report. Incident hip and wrist fractures were determined by physician adjudication of radiology reports (mean follow‐up, 9.8 years) and spine fractures by morphometric criteria on serial radiographs. The relationship of parity to hip and wrist fracture was assessed by proportional hazards models. Spine fracture risk was evaluated by logistic regression. Compared with parous women, nulliparous women (n = 1835, 19%) had an increased risk of hip and spine, but not wrist, fractures. In multivariate models, parity remained a significant predictor only for hip fracture. Nulliparous women had a 44% increased risk of hip fractures independent of hip bone mineral density (hazards ratio, 1.44; 95% CI, 1.17‐1.78). Among parous women, each additional birth reduced hip fracture risk by 9% (p = 0.03). Additionally, there were no differences in mean total hip, spine, or radial bone mineral density values between nulliparous and parous women after multivariate adjustment. In conclusion, childbearing reduces hip fracture risk by means that may be independent of hip bone mineral density.

Newborn Size Among Obese Women With Weight Gain Outside the 2009 Institute of Medicine Recommendation

OBJECTIVE: To estimate risk of delivering macrosomic, large-for-gestational-age and small-for-gestational-age neonates in obese women with gestational weight gain outside the 2009 Institute of Medicine recommendation (11–20 pounds). METHODS: In a retrospective cohort study, we evaluated 2,080 obese women (body mass index 30 or higher) with singleton pregnancies that resulted in term live births within one health maintenance organization between 2000 and 2005; women with diabetes or hypertensive disorders were excluded. Gestational weight gain was categorized as less than 0, 0 to less than 11, 11–20 (referent), greater than 20–30, greater than 30–40, and greater than 40 pounds and as above, below, or within Institute of Medicine recommendations. We conducted multivariable logistic regression to estimate the odds of large for gestational age and small for gestational age (birth weights greater than the 90th percentile and less than the 10th percentile for gestational age, respectively) and macrosomia (greater than 4,500 g) adjusting for potential confounders. RESULTS: Eighteen percent gained below, 25% within, and 57% above Institute of Medicine recommendations. Prevalence of macrosomia, large for gestational age, and small for gestational age were 4.3%, 19.8%, and 4.3%, respectively. Compared with weight gain of 11–20 pounds, weight gain above recommendations did not significantly decrease small-for-gestational-age risk but was associated with increased odds of macrosomia (adjusted odds ratio [OR] 3.36; 95% confidence interval [CI] 1.74–6.51; 6.0% compared with 2.1%) and large for gestational age (adjusted OR 1.80; 95% CI 1.36–2.38; 23.8% compared with 16.6%). Weight gain below recommendations was associated with increased odds of small for gestational age (adjusted OR 3.94; 95% CI 2.04–7.61; 8.8% compared with 2.7%) and decreased odds of large for gestational age (adjusted OR 0.56; 95% CI 0.37–0.84; 11.2% compared with 16.6%). CONCLUSION: Regarding small for gestational age and large for gestational age, there is no benefit of weight gain above Institute of Medicine recommendations. Weight gain below recommendations decreases large for gestational age but increases small-for-gestational-age risk. LEVEL OF EVIDENCE: II

WHO absolute fracture risk models (FRAX): Do clinical risk factors improve fracture prediction in older women without osteoporosis?

Bone mineral density (BMD) is a strong predictor of fracture, yet most fractures occur in women without osteoporosis by BMD criteria. To improve fracture risk prediction, the World Health Organization recently developed a country‐specific fracture risk index of clinical risk factors (FRAX) that estimates 10‐year probabilities of hip and major osteoporotic fracture. Within differing baseline BMD categories, we evaluated 6252 women aged 65 or older in the Study of Osteoporotic Fractures using FRAX 10‐year probabilities of hip and major osteoporotic fracture (ie, hip, clinical spine, wrist, and humerus) compared with incidence of fractures over 10 years of follow‐up. Overall ability of FRAX to predict fracture risk based on initial BMD T‐score categories (normal, low bone mass, and osteoporosis) was evaluated with receiver‐operating‐characteristic (ROC) analyses using area under the curve (AUC). Over 10 years of follow‐up, 368 women incurred a hip fracture, and 1011 a major osteoporotic fracture. Women with low bone mass represented the majority (n = 3791, 61%); they developed many hip (n = 176, 48%) and major osteoporotic fractures (n = 569, 56%). Among women with normal and low bone mass, FRAX (including BMD) was an overall better predictor of hip fracture risk (AUC = 0.78 and 0.70, respectively) than major osteoporotic fractures (AUC = 0.64 and 0.62). Simpler models (eg, age + prior fracture) had similar AUCs to FRAX, including among women for whom primary prevention is sought (no prior fracture or osteoporosis by BMD). The FRAX and simpler models predict 10‐year risk of incident hip and major osteoporotic fractures in older US women with normal or low bone mass.

Early Term Delivery and Health Care Utilization in the First Year of Life

OBJECTIVE To assess health care utilization during the first year of life among early term-born infants. STUDY DESIGN We assessed health care utilization of 22420 singleton term infants (37-42 weeks gestational age [GA]) without major birth defects, fetal growth restriction, or exposure to diabetes or hypertension in utero, delivered between 1998 and 2007 and continuously enrolled at Kaiser Permanente Northwest for 12 months after delivery. GA, duration of delivery hospitalization, and postdelivery rehospitalizations and sick/emergency room visits in the first year of life were obtained from electronic medical records. Logistic regression models were used to estimate associations between GA and number of hospitalizations and length of stay. Generalized linear models were used to estimate the adjusted mean number of sick/emergency visits. RESULTS Overall, 20.9% of term infants were born early. Infants delivered vaginally at 37 weeks GA had a 2.2 greater odds (95% CI, 1.6-3.1) of staying 4 or more days compared with those born at 39-40 weeks GA. Similar association was found among infants delivered by cesarean delivery at 37 or 38 weeks GA. Infants born at 37 weeks GA had increased odds of being rehospitalized within 2 weeks of delivery (OR, 2.6; 95% CI, 1.9-3.6). The adjusted mean number of sick/emergency room visits was higher for infants born at 37 and 38 weeks GA than for those born at 39-40 weeks GA (8.1, 7.7, and 7.3, respectively; P < .0001). CONCLUSIONS Early term-born infants had greater health care utilization during their entire first year of life than infants born at 39-40 weeks GA.

Associations Between 25-Hydroxyvitamin D and Weight Gain in Elderly Women

BACKGROUND 25-Hydroxyvitamin D [25(OH)D] levels are lower in obese individuals. Determining whether low vitamin D status can predispose weight gain requires a longitudinal study. METHODS From a community-based multicenter U.S. prospective cohort of 9704 (Study of Osteoporotic Fractures [SOF]), 4659 women aged ≥65 with baseline 25(OH)D measurement were followed for 4.5 years. They were weighed at baseline and follow-up visits, and a subset (n=1054) had 25(OH)D levels remeasured at follow-up. RESULTS Women with 25(OH)D levels ≥30 ng/mL had lower baseline weight (141.6 pounds) compared to women with 25(OH)D levels <30 ng/mL (148.6 pounds) (p<0.001). Overall, 25(OH)D status was not associated with weight change over 4.5 years, although there was a significant interaction between 25(OH)D status and weight change category (loss, gain, stable) (p<0.0001). In women who gained ≥5% weight, those with baseline 25(OH)D levels ≥30 ng/mL gained 16.4 pounds (12.2% of baseline weight) over 4.5 years compared to 18.5 pounds (13.9% of baseline weight) in women with levels <30 ng/mL (p=0.04). In women who lost ≥5% weight or remained stable (<5% weight change), there was no association between 25(OH)D status at baseline and weight change. Among women who gained weight and had 25(OH)D measured at both visits, having sustained or developing 25(OH)D levels ≥30 ng/mL was associated with less weight gain between visits (14.81 vs. 16.34 pounds, p=0.04). CONCLUSIONS Higher 25(OH)D levels are associated with lower weight gains, suggesting low vitamin D status may predispose to fat accumulation.

Health Care Utilisation in the First Year of Life Among Infants of Mothers With Perinatal Depression or Anxiety

BACKGROUND Limited information is available on associations between maternal depression and anxiety and infant health care utilisation. METHODS We analysed data from 24 263 infants born between 1998 and 2007 who themselves and their mothers were continuously enrolled for the infants first year in Kaiser Permanente Northwest. We used maternal depression and anxiety diagnoses during pregnancy and postpartum to categorise infants into two depression and anxiety groups and examined effect modification by timing of diagnosis (pregnancy only, postpartum only, pregnancy and postpartum). Using generalised estimating equations in multivariable log-linear regression, we estimated adjusted risk ratios (RR) between maternal depression and anxiety and well baby visits (<5 and ≥ 5), up to date immunisations (yes/no), sick/emergency visits (<6 and ≥ 6) and infant hospitalisation (any/none). RESULTS Infants of mothers with perinatal depression or anxiety were as likely to attend well baby visits and receive immunisations as their counterparts (RR = 1.0 for all). Compared with no depression or anxiety, infants of mothers with prenatal and postpartum depression or anxiety, or postpartum depression or anxiety only were 1.1 to 1.2 times more likely to have ≥ 6 sick/emergency visits. Infants of mothers with postpartum depression only had marginally increased risk of hospitalisation (RR = 1.2 [95% confidence interval 1.0, 1.4]); 70% of diagnoses occurred after the infants hospitalisation. CONCLUSIONS An understanding of the temporality of the associations between maternal depression and anxiety and infant acute care is needed and will guide strategies to decrease maternal mental illness and improve infant care for this population.

Surgical menopause and nonvertebral fracture risk among older US women

ObjectiveThe aim of this study was to determine whether older postmenopausal women with a history of bilateral oophorectomy before natural menopause (surgical menopause) have a higher risk of nonvertebral postmenopausal fracture than women with natural menopause. MethodsWe used 21 years of prospectively collected incident fracture data from the ongoing Study of Osteoporotic Fractures, a cohort study of community-dwelling women without previous bilateral hip fracture who were 65 years or older at enrollment, to determine the risk of hip, wrist, and any nonvertebral fracture. &khgr;2 and t tests were used to compare the two groups on important characteristics. Multivariable Cox proportional hazards regression models stratified by baseline oral estrogen use status were used to estimate the risk of fracture. ResultsBaseline characteristics differed significantly among the 6,616 women within the Study of Osteoporotic Fractures who underwent either surgical (1,157) or natural (5,459) menopause, including mean age at menopause (44.3 ± 7.4 vs 48.9 ± 4.9 y, P < 0.001) and current use of oral estrogen (30.2% vs 6.5%, P < 0.001). Fracture rates were not significantly increased for surgical versus natural menopause, even among women who had never used oral estrogen (hip fracture: hazard ratio [HR], 0.87; 95% CI, 0.63-1.21; wrist fracture: HR, 1.10; 95% CI, 0.78-1.57; any nonvertebral fracture: HR, 1.11; 95% CI, 0.93-1.32). ConclusionsThese data provide some reassurance that the long-term risk of nonvertebral fracture is not substantially increased for postmenopausal women who experienced premenopausal bilateral oophorectomy, compared with postmenopausal women with intact ovaries, even in the absence of postmenopausal estrogen therapy.

Weight Trajectory over 20 Years and Likelihood of Mild Cognitive Impairment or Dementia Among Older Women

The association between weight change and cognition is controversial. We examined the association between 20‐year weight change and cognitive function in late life.

Nulliparity and Osteoporotic Fracture Risk

We thank Drs Robbins, Schott, and Meunier for validating our results that nulliparity increases the risk of hip fracture in older women among their large EPIDOS cohort. The importance of replication among different study settings is a critical piece for scientific proof of causality of any study’s initial findings which we endorse. We now have several additional years of follow-up of the Study of Osteoporotic Fractures cohort (SOF), which now makes the age of our cohort more closely comparable with what Robbins et al. presented with EPIDOS. We have done additional analyses to allow better comparison between the two cohorts. Among our 9704 SOF women, with now an average of 12.8 years of follow-up available for analysis, there were 926 fractures. The average age of the SOF cohort was 71.7 years at the baseline exam, and thus the average age of survivors after 13 years of follow-up is essentially identical to Drs Robbins, Schott, and Meunier’s findings from EPIDOS. Furthermore, both cohorts are of primarily Northern European ancestry—the highest risk group for osteoporosis—although environmental and/or lifestyle differences may be likely between their cohort and ours. We first did ageand weight-adjusted Cox proportional hazards models to mirror the EPIDOS analysis, and nulliparous women in SOF had an increased risk of hip fracture (HR 1.20; 95% CI, 1.03–1.41). As the issue raised by Robbins et al. is the contribution of bone mineral density (BMD) to this risk of hip fracture among nulliparous women, we next limited our analyses to the 7928 SOF women who also had BMD measured at our second visit in 1989–1990. Among this group, there were 754 hip fractures—the strong relationship of nulliparity to increase hip fracture remained significant after adjustment for BMD (HR 1.26; 95% CI, 1.06–1.49). Further multivariate adjustment for covariates used in our original paper with BMD was similar (HR 1.31; 95% CI, 1.10–1.55). We would like to note that when we initially tested for a relationship between parity and hip fracture with BMD in SOF, this relationship was borderline significant after multivariate adjustment (mean duration of follow-up at that time was 4.1 years). However, with longer follow-up and additional hip fracture cases, the effect of nulliparity on increasing hip fracture risk became evident. We would argue that the effect size did not change appreciably in the EPIDOS study with the addition of BMD (HR decreased from 1.38 to 1.31), and that it is very possible with additional follow-up that the EPIDOS study will also find this increased risk is significant after adjustment for BMD. We completely agree with Drs Robbins, Schott, and Meunier that the clinically important time for hip fractures is in older women of ages similar to the women in the SOF and EPIDOS cohorts. However, we respectfully disagree that clinicians should consider only BMD when assessing a women’s risk of hip fracture—our results would suggest increasing parity operates through a different mechanism than is detected by BMD to increase an older women’s risk of hip fracture.