Effects of Di(2-ethylhexyl)phthalate on Bone Metabolism in Ovariectomized Mice

BACKGROUND: The molecular pathways of how endocrine disruptors affect bone mineral density (BMD) and bone remodeling are still unclear. The purpose of this experimental study is to determine the effects of di(2-ethylhexyl)phthalate (DEHP) on bone metabolism in ovariectomized mice. METHODS: Twenty-six-month-old female CD-1 mice were divided into 4 groups: control, low-dose DEHP, high-dose DEHP, and estrogen groups (n=5, each group). All mice were subjected to ovariectomy for the induction of artificial menopause and then exposed to corn oil, DEHP, and estrogen for 2 months. Micro-computed tomography (Micro-CT) of the bone and analysis of blood samples for bone markers were performed to observe the changes in bone metabolism. RESULTS: Osteocalcin level was decreased in the control, low-dose and high-dose DEHP group, the reduction width was greater in the high-dose DEHP group (−0.219 ng/mL) than control group (−0.077 ng/mL, P<0.05). C-terminal telopeptide of type I collagen level was increased in the control, low-dose and high-dose DEHP group, the increase range of low-dose DEHP group (0.329 ng/mL) showed greater than control group (0.093 ng/mL, P<0.05). Micro-CT analysis revealed that the BMD was significantly lower in the high-dose DEHP group (19.8×10⁻² g/cm³) than control group (27.2×10⁻² g/cm³, P<0.05). The structure model index was significantly higher in the high-dose DEHP group (2.737) than low-dose DEHP group (2.648) and estrogen group (2.63, P<0.05). It means the progression of osteoporosis in the high-dose DEHP group. CONCLUSIONS: These results confirm the negative effects of DEHP on bone health in ovariectomized mice. Further continuous studies on genetic pathways and other endocrine disruptors will be necessary to validate these findings.

Relationship between age at last delivery and age at menopause: The Korea National Health and Nutrition Examination Survey

OBJECTIVE: We used data from the 2010 to 2012 Korean National Health and Nutrition Examination Surveys to investigate whether the age at menopause is related to age at last delivery. METHODS: This was a cross-sectional study of the data for 714 women who became menopausal within the 3 years preceding the Korean National Health and Nutrition Examination Survey. RESULTS: Smoking, exercise, drink, educational level, and income were adjusted in model 1, and the mean ages at menopause were 50.5±0.3, 51.2±0.2, 51.2±0.3, and 50.2±0.4 years for women with <25, ≥25 and <30, ≥30 and <35, ≥35 years age at last delivery, respectively (P=0.049). Smoking, exercise, drink, educational level, income, age at first delivery, age at last delivery, and gravidity were adjusted in model 2, and the respective mean ages at menopause were 50.5±0.5, 50.7±0.4, 50.3±0.4, and 49.2±0.5 years (P=0.03). In both models, older age at last delivery showed higher age at menopause compared with women with younger age at last delivery. CONCLUSION: Korean women with older age at last delivery were associated with younger age at menopause. Increased number of pregnancies was related to older age at menopause.

Ovarian Volume in Korean Women with Polycystic Ovary Syndrome and Its Related Factors

OBJECTIVES: The aim of this study was to determine the relationship of ovarian volume (OV) to age, height, and weight in Korean young women with the polycystic ovary syndrome (PCOS) undergoing ultrasonography (US) and to investigate the relationship between ovarian follicle count and volume on US and serum hormone levels including the levels of the anti-Müllerian hormone (AMH) and gonadotropin. METHODS: A total of 272 Korean nulliparous women aged 15 to 39 years who were newly diagnosed with PCOS at a university hospital were included in this study. Evaluation of the ovaries and measurement of OVs in all cases were randomly performed by ultrasound. The OV and follicle number (FN) were obtained in all cases. RESULTS: In Korean women with PCOS, mean OV was 7.9 ± 3.6 cm3 (right) and 6.7 ± 3.1 cm3 (left). Mean FN in the PCOS group was 14.2 ± 4.6 (right) and 13.8 ± 4.3 (left). OV and ovarian FN were unrelated to patient weight, height and body mass index. The left ovarian FN was related to patient age. AMH levels ranged from 5.31 to 43.1 ng/mL and the mean level was 13.9 ± 7.2 ng/mL. Serum AMH was related to OV and FN, and serum total testosterone was related to FN in Korean women with PCOS. CONCLUSIONS: In Korean nulliparous women with PCOS, OV was smaller than that in other ethnic groups and the right OV was larger than the left OV. Ovarian FN, AMH, testosterone are good markers for the diagnosis of PCOS in Korean women.