The Role of Vitamin D in Menopause: Relationship to Menopausal Symptoms in Body Composition

Overview

Specific Aim 1: To compare effects of Vitamin D supplementation to usual care on symptoms in women transitioning to early postmenopause and determine the associated effect size in order to conduct a power analysis for a future RCT. Hypothesis: Vitamin D insufficient women in early postmenopause who are randomized to supplementation, titrated to achieve sufficiency for 2 months, will have fewer symptoms including hot flashes, mood, and musculoskeletal complaints than women randomized to usual care. Specific Aim 2: To compare effects of Vitamin D supplementation to usual care on body composition (by dual-energy x-ray absorptiometry \[DXA\] and by weight, BMI, waist to hip ratio) in overweight/obese women transitioning to early postmenopause and determine the associated effect size for a power analysis for a future RCT. Hypothesis: Vitamin D insufficient women in the menopausal transition randomized to supplementation, titrated to achieve sufficiency for 9 months, will improve DXA body composition (less total body and abdominal fat), compared to women in usual care, who will have increased body weight, including total and abdominal fat. Specific Aim 3: To estimate the proportion of overweight/obese middle-aged women who achieve sufficiency by 1 month versus 2 or more months and to determine if achieving sufficiency by 1 month varies by baseline characteristics. Hypothesis: About 80% of participants will achieve sufficient Vitamin D level by 1 month. Those who need more than 1 month for sufficiency will have lower baseline levels and higher initial BMI.

It is increasingly recognized that Vitamin D deficiency affects more than just bone health. Links between Vitamin D deficiency have been established or purported for diabetes, the metabolic syndrome, cardiovascular disease, and cancer. We propose to explore if Vitamin D replacement (safe, readily available, and inexpensive) has beneficial effects on 2 novel outcomes in early postmenopausal women: menopause-related symptoms and body composition. Most women transitioning through menopause, especially those with higher percent body fat, will experience hot flashes through a mean of 4 to 5 years. Many also have mood disturbances and muscle aches although the link with the menopausal transition is less clear. In many, these symptoms are severe enough to negatively impact their quality of life, work performance, and interpersonal relationships. Current treatments for menopause-related symptoms, such as menopausal hormone therapy, antidepressants, and anticonvulsants, have significant side effects and serious long term adverse consequences and symptoms recur after treatment discontinuation. A safe, inexpensive, well-tolerated treatment is therefore of high priority. Both our preliminary data in early postmenopausal women and a 2010 publication of women on aromatase inhibitors for breast cancer show an association between Vitamin D deficiency and menopause-related symptoms including hot flashes. It is postulated that a contributor to hot flashes is a menopausal decline in serotonin, a neurotransmitter with known effects on thermoregulation. As Vitamin D can protect against experimental serotonin depletion in rats, one proposed mechanism for symptom alleviation is prevention of serotonin decline in menopause. Both Vitamin D deficiency and the menopausal transition are associated with mood disturbances and musculoskeletal aches. Because estrogen increases the activity of the enzyme responsible for activating Vitamin D, the fall in estrogen that occurs during the menopausal transition could uncover previously subclinical Vitamin D deficiency. Indeed, Vitamin D can improved mood and muscle aches in non-menopausal populations, but its effects in menopausal women, where the benefits may be magnified, have not been previously studied.