BMI misclassification, leptin, C-reactive protein, and interleukin-6 in young women with differing levels of lean and fat mass

Association between waist circumference and female infertility in the United States

BACKGROUND

Obesity has significant implications for fertility and reproductive health. However, evidences linking abdominal obesity to female infertility were limited and inconclusive. Our objective was to figure out the potential relationship between waist circumference (WC) and infertility among women of childbearing age in the United States using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

Our cross-sectional study included 3239 female participants aged 18-45 years. To explore the independent relationship between WC and female infertility, the weighted multivariable logistic regression and smoothed curve fitting were performed. Interaction and subgroup analyzes were then conducted for secondary analysis.

RESULTS

WC was positively associated with female infertility independent of BMI after adjusting for BMI and other potential confounders. In fully adjusted model, for every 1cm increase in waist circumference, the risk of infertility increased by 3% (OR = 1.03, 95% CI: 1.01-1.06). When WC was divided into five equal groups, women in the highest quintile had 2.64 times risk of infertility than that in the lowest quintile (OR = 2.64, 95% CI: 1.31-5.30). Smooth curve fitting revealed a non-linear but positively dose-dependent relationship between WC and female infertility. Furthermore, we found an inverted U-shaped relationship (turning point: 113.5 cm) between WC and female infertility in participants who had moderate recreational activities and a J-shaped relationship (turning point: 103 cm) between WC and female infertility in participants who had deficient recreational activities.

CONCLUSIONS

Waist circumference is a positive predictor of female infertility, independent of BMI. Moderate recreational activities can lower the risk of female infertility associated with abdominal obesity.

Waist circumference in relation to outcomes of infertility treatment with assisted reproductive technologies

BACKGROUND

Many studies have documented a lower likelihood of live birth with increasing body mass index among women undergoing assisted reproductive technology, but few have examined the association with waist circumference, an anthropometric measure that allows assessment of central adiposity.

OBJECTIVE

To examine the relation between baseline waist circumference and infertility treatment outcomes among women undergoing treatment with assisted reproductive technology.

MATERIALS AND METHODS

We followed up 264 women who underwent 445 assisted reproductive technology cycles for infertility treatment at the Massachusetts General Hospital between 2010 and 2017. Waist circumference was assessed at enrollment. We used cluster-weighted generalized estimating equation models to estimate the probability of live birth by tertiles of waist circumference (<77, 77-86, >86 cm), while accounting for multiple treatment cycles per woman and adjusting for age, race, smoking, infertility diagnosis, day 3 follicle-stimulating hormone, body mass index, and height.

RESULTS

Mean (standard deviation) waist circumference and body mass index were 83.6 (12.6) cm and 24.1 (4.3) kg/m², respectively. Waist circumference and body mass index were positively correlated (r = 0.69, P < .0001). Waist circumference was inversely related to the probability of live birth after adjusting for BMI and other confounders. The multivariable adjusted probability of live birth (95% confidence interval) for women in increasing tertiles of waist circumference were 53% (42-65%), 42% (32-53%), and 38% (28-50%) (P, trend = .04). When women were classified in joint categories of body mass index and waist circumference, women with a body mass index ≥25 kg/m² and a waist circumference ≥77 cm had the lowest live birth rate (38% [27-50%]), whereas women with a body mass index between 18.5 and 25 kg/m² and a waist circumference <77 cm had the highest (54% [42-66%]). The results were similar using different waist circumference cut-off values.

CONCLUSION

Waist circumference was inversely related to the probability of live birth among women undergoing assisted reproductive technology independently of body mass index.

Skeletal growth, body composition, and metabolic risk among North Sudanese immigrant children

OBJECTIVES

Children of immigrants and refugees from developing countries are at risk for poor growth that could contribute to adult chronic disease. This study describes the physical growth, bone growth, body composition, metabolic risks, physical activity, and food security of Sudanese children living in the United States.

DESIGN AND SAMPLE

Cross-sectional descriptive study of 64 Sudanese children age 5-18.

MEASURES

Bone mineral content (BMC), bone density (aBMD), and body composition (fat, lean mass, percent body fat) were measured using DXA. Lipids, insulin, glucose, and hs-CRP were analyzed using standardized laboratory methods. Food security was assessed with the U.S. Household Food Security Survey. Physical activity was measured through self-report questionnaire and pedometers.

RESULTS

About 1/3 of children had low BMC and aBMD. Lean mass was low in 46%, and 32% were obese. Cholesterol, triglycerides, and HOMA-IR were elevated in 23.4%, 32.8%, and 15.6% of children, respectively; only 22% of children were physically active and 40% experienced food insecurity.

CONCLUSION

Sudanese children may have unique risks related to low bone mass low muscle mass, high percent body fat metabolic biomarkers, inactivity, and food insecurity potentially contributing to adult osteoporosis, diabetes, and cardiovascular disease.

Interactive associations of physical activity, adiposity, and oral contraceptive use on C-reactive protein levels in young women

Oral contraceptives (OCs) are the most frequently used type of birth control among young women. OC-users have higher C-reactive protein (CRP) values, an indicator of systemic inflammation, than do non-OC-users. In addition, adiposity (percent fat) is positively associated with CRP, and physical activity (PA) is inversely associated with CRP. The present study determined the interactive associations of PA, percent fat, and OC-use with CRP. Data were collected during 2012-2015 at the University of Georgia. Objective PA was measured via pedometers. Percent fat was measured via dual X-ray absorptiometry. The current OC-use was self-reported. High-sensitivity (hs) CRP was determined using venipuncture. Multivariate linear regression determined the interactive associations of percent fat, OC-use, and PA with hs-CRP. Participants (n = 247; mean age 18.9 ± 1.4 years, 60.7 percent white) accumulated a mean of 10,075.7 ± 3,593.4 steps/day. One-third of participants were categorized as overweight/obese by BMI (mean = 24.5 ± 4.8 kg/m², mean percent fat = 35.2 ± 6.8). The current OC-use was reported by 26.2 percent of the sample (n = 61). A significant three-way interaction (β = 0.01, p = .03) indicated that higher PA was associated with lower hs-CRP in non-OC-users with higher percent fat, but not among OC-users with higher percent fat. These results highlight the need to measure and account for the current OC-use in studies examining the relationship between PA and CRP.

Changes of 25-OH-Vitamin D during Overwintering at the German Antarctic Stations Neumayer II and III

Purpose

Humans in Antarctica face different environmental challenges, such as low ultra-violet radiation, which is crucial for vitamin D production in humans. Therefore we assessed changes in 25-OH-vitamin D serum concentration during 13 months of overwintering at the German Stations Neumayer II and III (2007–2012). We hypothesized that (i) 25-OH-vitamin D serum concentration would significantly decrease, (ii) changes would be affected by age, gender, baseline (i.e. pre-overwintering) fat mass, baseline 25-OH-vitamin D serum concentration, and station residence, and (iii) our results would not differ from similar previous studies in comparable high latitudes.

Materials & Methods

25-OH-vitamin D serum concentrations were determined before, after, and monthly during the campaigns from venous blood samples of n = 43 participants (28 men, 15 women). Baseline fat mass was determined via bio impedance analysis and body plethysmography. Data were analyzed for change over time, dependency on independent parameters, and after categorization for sufficiency (>50nmol/l), insufficiency (25-50nmol/l), and deficiency (<25nmol/l). Results were compared with data from similar previous studies.

Results

We found a significant decrease of 25-OH-vitamin D with dependency on month. Age, gender, fat mass, and station residence had no influence. Only baseline 25-OH-vitamin D serum concentrations significantly affected subsequent 25-OH-vitamin D values.

Conclusions

Overwinterings at the Antarctic German research stations Neumayer II and III are associated with a decrease in 25-OH-vitamin D serum concentrations, unaffected by age, gender, baseline fat mass, and station residence. Higher baseline vitamin D serum concentrations might protect from subsequent deficiencies. Residence at the Neumayer Stations may lead to lower vitamin D serum concentrations than found in other comparable high latitudes.