Association of blood lead and cadmium levels with the age of menarche and menopause using the Korea National Health and Nutrition Examination Survey

Abstract

Background Heavy metal accumulation in the body can cause many health problems, among them lead (Pb) and cadmium (Cd) are well-known as reprotoxic substances. However, very limited information has been reported exposure to environmental heavy metals directly affects reproductive life span of female. This study aimed to investigate the association between exposure to environmental lead and cadmium and the age at menarche and menopause of the general population in South Korea.Methods We selected subjects among 22,629 females who participated in the 2010~2017 (exclude 2014, 2015) Korean National Health and Nutrition Examination Survey. We calculated odds ratio (OR) and 95% confidence interval of proportion of the girls who started their menarche and women who stepped into the menopause stage by continuous levels of blood lead and cadmium and quartiles of them.Results The geometric mean (GM) of blood lead and cadmium levels were 1.02 µg/dL and 0.28 µg/L (10~15 years of age 516 girls), respectively. And the GM of blood lead and cadmium levels were 1.85 µg/dL and 1.33 µg/L (46~55 years of age 1,004 women), respectively. In adjusted logistic regression models, as the blood lead levels increased, the proportion of the menarche has significantly decreased [OR=0.24 (0.09, 0.64)]. On the other side, the proportion of the menopause has significantly increased [OR=4.51 (2.52, 8.06)]. In addition, as the blood cadmium levels increased, the proportion of the menarche has significantly increased [OR=2.78 (1.31, 5.94)], and proportion of the menopause stage has significantly decreased [OR=0.43 (0.27, 0.70)].Conclusions Our results suggested two novel insights. Firstly, higher blood lead levels could delay menarche and cause early menopause. Secondly, higher blood cadmium levels could cause early menarche and delay menopause. Consequently, exposure to environmental lead and cadmium may affects reproductive life span of female.