The influence of environmental factors on premature ovarian insufficiency and ovarian aging.

Premature ovarian insufficiency and ovarian aging are complex conditions that affect women's reproductive health and overall well-being. They are both characterized by hypergonadotropic hypogonadism and infertility, and together affect about 1 in 100 women by the age of 40. This review explores the influence of environmental factors on the development and progression of premature ovarian insufficiency and ovarian aging. When referring to environmental factors, we include a wide range of external agents and conditions, including chemicals, socioeconomic factors and lifestyle choices. Through a review of the literature, we attempt to highlight the link between environmental factors and ovarian health. We examine the impact of endocrine-disrupting chemicals, such as bisphenol A and phthalates, on ovarian function and investigate the mechanisms by which these chemicals can disrupt hormone signaling pathways, leading to alterations in ovarian reserve, oocyte quality, and folliculogenesis. Moreover, we explore lifestyle factors like obesity, stress, smoking and alcohol in relation to their effects on ovarian aging. Epigenetic changes may play a crucial role in the prevalence of premature ovarian insufficiency. Understanding the impact of environmental factors on premature ovarian insufficiency and ovarian aging is very important in public and clinical health contexts. By identifying risk factors, healthcare providers can develop targeted and strategic prevention and intervention plans. Furthermore, this knowledge can promote reproductive health and minimize exposure to harmful environmental agents.

Diabetes mellitus in the era of climate change.

Worldwide, diabetes mellitus (DM) represents a major public-health problem due to its increasing prevalence in tandem with the rising trend of obesity. However, climate change, with its associated negative health effects, also constitutes a worrisome problem. Patients with DM are experiencing more visits to emergency departments, hospitalizations, morbidity and mortality during heat waves at ever-increasing numbers. Such patients are particularly vulnerable to heat waves due to impaired thermoregulatory mechanisms in conjunction with impaired autonomous nervous system responses at high temperatures, electrolyte imbalances and rapid deterioration of kidney function, particularly among those aged > 80 years and with preexisting chronic kidney disease (CKD). Moreover, exposure to cold temperatures is associated with increased rates of acute myocardial infarction as well as poor glycaemic control, although results are conflicting regarding cold-related mortality among patients with DM. In addition to extremes of temperature, air pollution as a consequence of the climate crisis may also be implicated in the increased prevalence and incidence of DM, particularly gestational DM (GDM), and lead to deleterious effects in patients with DM. Thus, more large-scale studies are now required to elucidate the association between specific air pollutants and risk of DM. This review presents the currently available evidence for the detrimental effects of climate change, particularly those related to weather variables, on patients with DM (both type 1 and type 2) and GDM. Specifically, the effects of heat waves and extreme cold, and pharmaceutical and therapeutic issues and their implications, as well as the impact of air pollution on the risk for DM are synthesized and discussed here.

Irisin in patients with nonalcoholic fatty liver disease.

OBJECTIVE: Irisin is a recently discovered myokine proposed to increase thermogenesis-related energy expenditure and improve metabolism. We aimed to comparatively evaluate serum irisin levels in patients with biopsy-proven nonalcoholic fatty liver disease (NAFLD) vs. controls and study their association with disease severity. METHODS: Fifteen and 16 consecutively enrolled patients with biopsy-proven nonalcoholic simple steatosis (NAFL) and steatohepatitis (NASH), respectively, and 24 lean and 28 obese controls without NAFLD were recruited. Irisin, established adipokines and biochemical tests were measured. RESULTS: Serum irisin levels were statistically different in obese controls (33.7±2.7 ng/mL; p<0.001) and patients with NAFL (30.5±1.5 ng/mL; p<0.001) and NASH (35.8±1.9 ng/mL; p=0.001) compared with lean controls (47.7±2.0 ng/mL), but were similar among patients with NAFL, NASH and obese controls. This difference remained significant after adjustment for body mass index (or waist circumference), gender, age, insulin resistance (assessed by HOMA-IR or QUICKI), exercise and time since blood collection. Serum leptin and adiponectin, but not irisin, levels were independently from BMI correlated with insulin resistance and cardiometabolic factors. Serum irisin tended to be higher in patients with (36.7±2.4 ng/mL) than without (30.8±1.2 ng/mL; p=0.02) portal inflammation and independently associated with the latter; these data need to be confirmed by future studies. CONCLUSIONS: Serum irisin levels differ between lean controls and obese controls or NAFLD patients. Despite similar circulating irisin levels between NAFL and NASH groups, irisin may be independently and positively associated with the presence of portal inflammation. Future clinical and mechanistic studies are needed to confirm and extend these data.

Circulating irisin in relation to insulin resistance and the metabolic syndrome.

CONTEXT: Irisin, a recently identified hormone, has been proposed to regulate energy homeostasis and obesity in mice. Whether irisin levels are associated with risk of the metabolic syndrome (MetS), cardiometabolic variables, and cardiovascular disease (CVD) risk in humans remains unknown. OBJECTIVE: Our objective was to assess the associations between baseline serum irisin levels and MetS, cardiometabolic variables, and CVD risk. DESIGN, SETTING, AND SUBJECTS: We conducted a comparative cross-sectional evaluation of baseline circulating levels of the novel hormone irisin and the established adipokine adiponectin with MetS, cardiometabolic variables, and CVD risk in a sample of 151 subjects. RESULTS: Baseline irisin levels were significantly higher in subjects with MetS than in subjects without MetS. Irisin was associated negatively with adiponectin (r = -0.4, P < .001) and positively with body mass index (r = 0.22, P = .008), systolic (r = 0.17, P = .04) and diastolic (r = 0.27, P = .001) blood pressure, fasting glucose (r = 0.25, P = .002), triglycerides (r = 0.25, P = .003), and homeostasis model assessment for insulin resistance (r = 0.33, P < .001). After adjustment for potential confounders, including body mass index, subjects in the highest tertile of irisin levels were more likely to have MetS (odds ratio [OR] = 9.44, 95% confidence interval [CI] = 2.66-33.44), elevated fasting blood glucose (OR = 5.80, 95% CI = 1.72-19.60), high triglycerides (OR = 3.89, 95% CI = 1.16-13.03), and low high-density lipoprotein cholesterol (OR = 3.30, 95% CI = 1.18-9.20). Irisin was independently associated with homeostasis model assessment for insulin resistance and general Framingham risk profile in multiple linear regression analyses after adjustment for confounders. Adiponectin demonstrated the expected associations with outcomes. CONCLUSIONS: Irisin is associated with increased risk of MetS, cardiometabolic variables, and CVD in humans, indicating either increased secretion by adipose/muscle tissue and/or a compensatory increase of irisin to overcome an underlying irisin resistance in these subjects.