Investigating the relationship between lifestyle and premature menopause

Menopause is the permanent cessation of menstruation due to the loss of ovarian follicle function and a decrease in circulating estrogen levels. Clinically, menopause is diagnosed after 12 months of amenorrhea, although women are born with one to two million primordial follicles and start menstruating with about 500,000 follicles, by age 40, perhaps only a few thousand follicles remain and only 300 to 400 primordial follicles ovulate during a woman's reproductive life, and the fewer eggs a woman has and the faster they are discharged, the sooner she will experience menopause. Ovarian follicles can be reduced in two ways: through a process called atresia or through ovulation. Atresia is a process of steady degeneration of follicles that actually begins in the female fetus and continues until menopause independent of the hormonal cycle, and symptoms associated with menopause include: hot flashes and night sweats. Hot flashes refer to a sudden feeling of heat in the face, neck, and chest, often accompanied by hot skin, sweating (perspiration), palpitations, and a feeling of acute physical discomfort that can last for several minutes, vaginal dryness, pain during sexual intercourse and urinary incontinence, difficulty sleeping or insomnia; and changes in mood, depression or anxiety, loss of bone density and heart disease. Most women experience menopause between the ages of 45 and 55 as a natural part of biological aging, but some women experience menopause earlier (before the age of 40) that this "early menopause" may be influenced by factors such as some Chromosomal abnormalities, autoimmune disorders, smoking, excessive weight loss, null parity and irregular menstruation, nutrition, intense exercise, sexual abuse in childhood, etc.Method:Current review by searching in authoritative books and useful databases such as Scopus, Elsevier, PubMed, Science Direct, Google Scholar, Mag Iran, Iran Dog, Iran Medex in the years 2010 to 2023 with keywords lifestyle, nutrition, exercise and physical activity, smoking , sexual abuse, obesity and premature menopause were done.Findings: 1. Smoking.One of the strongest and most obvious risk factors for early menopause is smoking. In general, women who smoke are likely to experience natural menopause a year earlier than non-smokers. Tobacco smoke contains polycyclic hydrocarbons that are toxic to ovarian germ cells and cause estrogen deficiency associated with follicular exhaustion. Alkaloid components of tobacco smoke, including nicotine and anabasine, reduce estrogen levels by interfering with its synthesis. Cigarette smoke compounds inhibit granulosa cell aromatase and other key enzymes in estrogen synthesis, which results in reduced estradiol production in vitro. Tobacco smoke components also cause a preferential shift of 2-hydroxylation over 16-hydroxylation of estrogen in smokers, leading to decreased estrogen activity. It is possible that alkaloids in tobacco smoke may have specific anti-estrogenic effects on the uterus, evidence suggests that an alkaloid from the root of Murraya paniculata can bind to uterine estrogen receptors. Finally, the effect of smoking on hypothalamic-pituitary function is also possible. In rats, tobacco smoke appears to delay or reduce the rise in LH hormone levels. Therefore, smoking affects ANP by reducing estrogen levels below the optimal level to support endometrial growth.2. Obesity. Higher peripheral production of estrogen in adipose tissue of obese women contributes to later onset of menopause. In addition, adipose tissue, as an endocrine and paracrine organ, produces a series of adipokines, including leptin. Leptin can act centrally in the hypothalamus and pituitary gland and peripherally in the ovary and reproductive tract, thereby helping to maintain normal reproductive function. In contrast, underweight may result in premature menopause as a result of malnutrition, excessive exercise, weight loss dieting, and concomitant or history of chronic disease (such as chronic obstructive pulmonary disease). In addition, less adipose tissue leads to lower leptin levels, which are associated with early menopause (under 45).