Toxic metals and the menopause

Abstract

Toxicity of chemicals and environmental pollutants may be expressed differently in women than in men. Until recently, most research involved men. With the initiation of studies on the effects of environmental pollutants in women, there is increasing evidence of effects at specific periods in a woman's life; however, accrual of data is slow. This review focuses on the kinetics and effects of the toxic metals lead and cadmium related to menopause. Data on other metals are extremely limited. One of the few well described examples of menopausal-related effects of metals is the very painful disease called Itai-itai, which is a combination of osteoporosis, osteomalacia and renal damage caused by consumption of cadmium-polluted rice. Recent data demonstrate mild effects of cadmium on both kidney and bone with present environmental exposure levels. Women may be at greater risk than men, because of increased gastrointestinal uptake of cadmium at low iron stores, which is common in women of childbearing age. Thus, improvement of iron status, which often occurs at menopause, has a positive effect on cadmium exposure in the sense that its absorption decreases. Cadmium accumulates in the kidney with a half-life of 10-30 years. The health effects appear around menopause, concurrent with the peak in renal cadmium concentrations. About 90% of body lead is localised to bone. There is a significant release of bone lead after the menopause, in association with the acceleration of bone resorption. Thus, postmenopausal women may be at increased risk of adverse effects of lead.