A perspective on the hormonal abnormalities of obesity: are they cause or effect?

An evaluation of adherence to folic acid supplementation in pregnant women during early gestation for the prevention of neural tube defects

OBJECTIVE

Neural tube defects (NTD) are potentially preventable by periconceptual folic acid supplementation. Women with obesity are at higher risk of NTD, therefore, are recommended a higher dose of 5 mg folic acid to mitigate this risk. The aim of this study was to evaluate maternal practice of folic acid supplementation amongst the antenatal population in relation to maternal obesity status.

DESIGN

Prospective observational study.

SETTING

Women ≤18 weeks' gestation at their first antenatal appointment attending University Maternity Hospital Limerick (Ireland) were recruited. Maternal height and weight were measured. Obesity was defined at a threshold of ≥30·0 kg/m2 and ≥27·5 kg/m2 when adjusting for ethnicity. A two-part questionnaire captured maternal characteristics and assessed supplementation compliance, commencement and dosage. Fisher's exact test for independence analysed differences in variables. A P value of <0·05 was considered significant.

PARTICIPANTS

A total of 328 women participated over a duration of 6 weeks.

RESULTS

Mean gestational age was 12·4 ± 1·4 weeks and mean BMI 26·7 kg/m2 ± 5·2 kg/m2. 23·8 % (n 78) were classified as obese. 96·5 % (n 315) were taking folic acid and 95·7 % (n 314) supplemented daily. 30·2 % (n 99) commenced supplementation 12 weeks prior to conception. Overall, 57·9 % (n 190) of women met folic acid supplementation dose requirements. 89·1 % (n 55) of women with obesity did not. Women with obesity were less likely to meet the higher folic acid supplementation dose requirements (P =< 0·001).

CONCLUSION

Folic acid supplementation practices within this cohort were suboptimal to prevent their risk of NTD. This study showed inadequate compliance of folic acid supplementation, and inadequate dosage for women with obesity. Increased patient education and awareness are needed within the antenatal period of pregnancy to bring folic acid supplementation practices in line with best practice guidelines.

Metanephrine and Normetanephrine Urine Excretion in Patients with PCOS

Aims: The present study aims to investigate the association between catecholamine metabolites (normetanephrine [NMN] and metanephrine [MN]) and polycystic ovarian syndrome (PCOS) and its clinical manifestations.

Materials and methods: A total of 60 female patients (18-37 years) were included in the study. Twenty-five healthy women and 35 patients with PCOS provided blood and urine samples. Anthropometric, biochemical, and hormonal parameters, e.g. immunoreactive insulin, total testosterone, gonadotropins, and dehydroepiandrosterone-sulfate (DHEAS) have been investigated. Twenty-four-hour urinary metanephrines (MN and NMN) were measured by radioimmunoassay technique.

Results: MN and NMN showed a strong positive correlation (r = +0.645, p < 0.001) in women with PCOS, but nephrines were not significantly associated with the hormonal, anthropometric, and metabolic parameters of the patients (p > 0.05 for all). No differences in urinary nephrines concentrations between women with PCOS and healthy individuals after adjustment for age and BMI were established. However, lower 24-hour urinary MN levels predicted the development of menstrual irregularity after adjustment for age and BMI (OR = 1,015 [95% CI 1,001-1,029], p = 0,036).

Conclusions: Adrenomedullary dysfunction might influence the development of chronic anovulation in young women.

Testosterone imbalance may link depression and increased body weight in premenopausal women

Accumulating evidence supports a link between depression and being overweight in women. Given previously reported sex differences in fat accumulation and depression prevalence, as well as the likely role of sex hormones in both overweight and mood disorders, we hypothesised that the depression-overweight association may be mediated by sex hormones. To this end, we investigated the association of being overweight with depression, and then considered the role of sex hormones in relation to being overweight and depression in a large population-based cohort. We included a total of 3124 women, 970 premenopausal and 2154 postmenopausal from the LIFE-Adult cohort study in our analyses. We evaluated associations between being overweight (BMI >25 kg/m²), sex hormone levels, and depressive symptomatology according to Centre for Epidemiologic Studies Depression (CES-D) scores, and explored mediation of depression in a mediation model. Being overweight was significantly associated with depressive symptoms in premenopausal but not postmenopausal women. Both premenopausal and postmenopausal overweight women had higher free testosterone levels compared with normal weight women. Premenopausal women with depressive symptomatology had higher free testosterone levels compared to women without. We found a significant mediation effect of depressive symptomatology in overweight premenopausal women through free testosterone level. These findings highlight the association between being overweight and depressed, and suggest that high free testosterone levels may play a significant role in depression of overweight premenopausal women. Based on this, pharmacological approaches targeting androgen levels in overweight depressed females, in particular when standard anti-depressive treatments fail, could be of specific clinical relevance.

Associations Between Anxiety, Body Mass Index, and Sex Hormones in Women

Background: Several studies have shown a positive association between anxiety and obesity, particularly in women. We aimed to study whether sex hormone alterations related to obesity might play a role in this association. Patients and methods: Data for this study were obtained from a population-based cohort study (the LIFE-Adult-Study). A total of 3,124 adult women (970 premenopausal and 2,154 postmenopausal) were included into the analyses. The anxiety symptomatology was assessed using the GAD-7 questionnaire (cut-off ≥ 10 points). Sex hormones were measured from fasting serum samples. Results: We did not find significant differences in anxiety prevalence in premenopausal obese women compared with normal-weight controls (4.8% vs. 5.5%). Both obesity and anxiety symptomatology were separately associated with the same sex hormone alteration in premenopausal women: higher total testosterone level (0.97 ± 0.50 in obese vs. 0.86 ± 0.49 nmol/L in normal-weight women, p = 0.026 and 1.04 ± 0.59 in women with vs. 0.88 ± 0.49 nmol/L in women without anxiety symptomatology, p = 0.023). However, women with anxiety symptomatology had non-significantly higher estradiol levels than women without anxiety symptomatology (548.0 ± 507.6 vs. 426.2 ± 474.0 pmol/L), whereas obesity was associated with lower estradiol levels compared with those in normal-weight group (332.7 ± 386.5 vs. 470.8 ± 616.0 pmol/L). Women with anxiety symptomatology had also significantly higher testosterone and estradiol composition (p = 0.006). No associations of sex hormone levels and BMI with anxiety symptomatology in postmenopausal women were found. Conclusions: Although both obesity and anxiety symptomatology were separately associated with higher testosterone level, there was an opposite impact of anxiety and obesity on estradiol levels in premenopausal women. We did not find an evidence that the sex hormone alterations related to obesity are playing a significant role in anxiety symptomatology in premenopausal women. This could be the explanation why we did not find an association between obesity and anxiety. In postmenopausal women, other mechanisms seem to work than in the premenopausal group.

Association Between Maternal Obesity and Autism Spectrum Disorder in Offspring: A Meta-analysis

As the link between maternal obesity and risk of autism among offspring is unclear, the present study assessed this association. A systematic search of an electronic database was performed to identify observational studies that examined the association between maternal obesity and autism. The outcome measures were odds ratios comparing offspring autism risk between obese and normal-weight mothers. Five observational studies were included in the meta-analysis. A fixed-effects model was used since low heterogeneity was observed between studies. The pooled adjusted odds ratio was 1.47 (95 % CI 1.24-1.74). The meta-analysis results support an increased risk of autism spectrum disorder in children of women who were obese during pregnancy. However, further study is warranted to confirm these results.

Maternal pre-pregnancy body mass index and offspring temperament and behavior at 1 and 2 years of age

Recent research suggests that fetal exposure to increased maternal body mass index (BMI) during pregnancy may be associated with psychopathology later in life. When this link first emerges, and if it is due to intrauterine exposures or confounding variables is not known. We therefore assessed associations between maternal pre-pregnancy BMI and: (1) temperament at 1 year of age, and (2) Child Behavior Checklist internalizing and externalizing scales at age 2 in the 2900 mothers and infants enrolled in the Western Australian Pregnancy Study. Pre-pregnancy BMI was positively associated with externalizing scores (β = 0.131, 95 % CI 0.013-0.249) at age 2, even after adjustment for confounders, but not with internalizing scores or an increased risk of difficult temperament. These data suggest that fetal exposure to increased maternal BMI is associated with elevated levels of behavior problems as early as age 2, and that this may be linked to the intrauterine environment.

Pre-pregnancy and pregnancy obesity and neurodevelopmental outcomes in offspring: a systematic review

Maternal obesity in pregnancy is associated with a number of adverse outcomes for mother and her offspring both perinatally and later in life. This includes recent evidence that suggests that obesity in pregnancy may be associated with central nervous system problems in the foetus and newborn. Here, we systematically review studies that have explored associations between maternal overweight and obesity in pregnancy and cognitive, behavioural and emotional problems in offspring. The 12 studies eligible for this review examined a wide range of outcomes across the lifespan and eight provided evidence of a link. These data suggest that the offspring of obese pregnancies may be at increased risk of cognitive problems and symptoms of attention deficit hyperactivity disorder in childhood, eating disorders in adolescence and psychotic disorders in adulthood. Given the limitations of existing data, these findings warrant further study, particularly in light of the current worldwide obesity epidemic.

Mechanisms of obesity-induced male infertility

Male infertility, characterized by hypogonadism, decreased semen quality or ejaculatory dysfunction, accounts for approximately 20% of infertility cases. Obesity and metabolic dysfunction have been identified, among other causal factors, to contribute to male infertility. In the context of the Western world's 'obesity epidemic', this article discusses three main biological mechanisms linking obesity to impaired male reproductive function: hypogonadism, testicular heat stress/hypoxia-induced apoptosis and endocrine disruption by 'obesogens'. Among these, obesity-induced hypogonadism is undoubtedly the most clinically significant and is easily assessed. Rapidly expanding areas of research in this area include leptin modulation of kisspeptins and hypothalamic-pituitary-testicular hormone pathways, and roles of other adipocytokines in male infertility, as well as the impact of exposure to obesogens on the quality of semen.

Does leptin play a role in obesity-asthma relationship?

The increase of asthma has paralleled the rising obesity during the past decades. Obesity is characterized by the increase of leptin in the circulation. Leptin is an obesity gene product, and it can stimulate the production of pro-inflammatory mediators, such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and interferon (IFN)-gamma. There is a link between leptin and asthma, especially in children. It remains unclear however, if leptin is in the pathway of obesity-asthma relationship and if it plays a distinctive role in asthma in obese vs. non-obese subjects. Since leptin is in a positive feedback loop with the pro-inflammatory cytokines such as TNF-alpha, there is a possibility that leptin is involved as a regulatory rather than an etiologic mechanism of asthma development. Weight loss is associated with decreased circulating leptin concentration in children. Weight control program may need to be considered in the treatment of asthma in obese children.

Maternal obesity and risk of neural tube defects: a metaanalysis

We conducted a metaanalysis of published evidence on the relationship between maternal obesity and the risk of neural tube defects (NTDs). Eligible studies were identified from 3 sources: (1) PubMed search of articles that were published from January 1980 through January 2007, (2) reference lists of publications that were selected from the PubMed search, and (3) reference lists of review articles on obesity and maternal outcomes that were published from January 2000 through January 2007. Twelve studies met inclusion criteria. A Bayesian random effects model was used for the metaanalysis and metaregression. Unadjusted odds ratios for an NTD-affected pregnancy were 1.22 (95% CI, 0.99-1.49), 1.70 (95% CI, 1.34-2.15), and 3.11 (95% CI, 1.75-5.46) among overweight, obese, and severely obese women, respectively, compared with normal-weight women. None of the study characteristics included in the metaregression analysis affected the results significantly. Maternal obesity is associated with an increased risk of an NTD-affected pregnancy.

Infrequent milk consumption plus being overweight may have great risk for asthma in girls

BACKGROUND

Inadequate milk consumption and being overweight are each associated with asthma symptoms in children. Milk consumption has been inversely related to childhood overweight. Thus, being overweight may be a pathway or a confounder in milk-asthma relationship. A combination of both factors may be associated with greater risk of asthma than one factor alone.

METHODS

This study included 246 children with allergist-diagnosed asthma and 477 nonasthmatic controls at the age of 8-10 years. Information on milk consumption during the last 12 months was obtained from questionnaires. Being overweight was defined as body mass index > or =85th percentile. Being overweight as a possible pathway or confounder was formally tested. The odds ratio (OR) for combined infrequent milk consumption and being overweight in asthmatic vs nonasthmatic children was determined in multivariate logistic regression analyses.

RESULTS

There was a significant interaction between milk consumption and sex of the child in relation to asthma. Asthma was significantly associated with infrequent milk consumption in girls (crude OR 2.11, 95% CI 1.05-4.24) but not in boys. The asthma-milk relation in girls was neither mediated by being overweight (p(mediation tests) = 0.27) nor was the relationship confounded by being overweight (a 9% change in coefficient). Asthmatic girls had 3.6 times increased odds of having combination of infrequent milk consumption and being overweight than nonasthmatic girls (adjusted OR 3.64, 95% CI 1.18-11.24). Asthma was not associated with either factor or with absence of the other in girls.

CONCLUSION

Infrequent milk consumption plus being overweight may have great risk for asthma in girls.

Plasma adrenal, gonadal, and conjugated steroids following long-term exercise-induced negative energy balance in identical twins

There are few reports of the change in sex hormone levels accompanying a weight change in men, although an excessive decline in testosterone (TESTO) has been described as an associate of stress-induced weight loss. Plasma levels of cortisol, TESTO, dihydrotestosterone (DHT), dehydroepiandrosterone sulfate (DHEA-S), androsterone glucuronide (ADT-G), and androstane-3alpha, 17beta-diol glucuronide (3alphaDIOL-G) were measured in seven pairs of sedentary male monozygotic twins (age, 21.0 +/- 0.8 years; body mass index [BMI], 26.2 +/- 5.5 kg/m2) before and after 93 days of standardized submaximal (50% to 55% maximum oxygen consumption) cycle-ergometer exercise. A total energy deficit of 244 +/- 9.7 MJ induced significant changes (P < .0001) in body weight ([BW] -5.0 +/- 2.2 kg) and body fatness measures. Plasma TESTO and DHEA-S increased and 3alphaDIOL-G decreased. The increase in TESTO was a significant inverse correlate of loss in all measures of body fat, particularly central adiposity (r = -.58 to -.86, P < .001, fat loss-adjusted). Lower postexercise levels of 3alphaDIOL-G correlated positively with decreased body composition measures (r = .65 to .68, P < .01). The increase in plasma TESTO accompanying the loss of abdominal visceral fat (AVF) was greater in men with lower fasting insulin levels (P < .0001). The baseline within-twin-pair resemblance in TESTO and 3alphaDIOL-G (intraclass correlation coefficients [ICC] = .83 and .78, respectively, P < .01) was lost with intervention. Cortisol, DHEA-S, and ADT-G developed within-twin-pair similarity (ICC adjusted for fat loss: cortisol, .72; ADT-G, .62, P < .05; DHEA-S, .85, P < .002). We conclude that a steroid profile characterized by high TESTO and low androgen metabolite levels accompanied the changes in body composition and body fat distribution generated by the exercise-induced negative energy balance. Furthermore, these changes were characterized by a significant resemblance within identical-twin pairs.

The endocrinology of obesity

Numerous endocrine alterations are associated with obesity (Table 1). The majority of the alterations are secondary to obesity and must be considered simply associated and potentially in the pathogenesis of the complications of obesity. The discovery of new endocrine peptides such as leptin that signal body fat content will increase our understanding of the regulation of body fat content. As a result, therapies will most certainly be developed that are directly targeted at the alterations in endocrine function.

The hypothalamic-pituitary-adrenal axis in obesity

The hypothalamic-pituitary-adrenal (HPA) axis normally maintains the concentration of cortisol within a narrow range with a diurnal variation characterized by higher cortisol concentrations in the morning and reduced levels in the evening. Excessive or deficient secretion of cortisol is associated with pathologic changes. Obesity has been linked with age, sex and racial alterations in the functioning of the HPA axis which are reviewed. The possible relationship of altered HPA axis activity with the long-term complications of obesity are considered.