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

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.

Inclusion criteria

• Women in late menopausal transition or early menopause
• Age 40-55
• BMI >25 kg/m2
• Suffer from menopausal symptoms
• Change in previously regular cycles consisting of at least ≥2 skipped cycles and an interval of amenorrhea (≥60 days) in the last year
• Negative pregnancy test
• Vitamin D insufficiency (<30 ng/ml)
• Weight stability (+/- 5%) for 3 months

Exclusion criteria

• No period for >12 months
• Hormone use (i.e. menopausal hormone therapy, oral contraceptive, other hormonal medications) in last 3 months
• History of hysterectomy more than 11 months ago
• Abnormal screening blood tests (i.e. elevated serum calcium level, elevated creatinine)
• History of medical conditions where Vitamin D supplementation is not indicated (i.e. chronic renal insufficiency, elevated calcium, sarcoidosis or other granulomatous disease, lymphoma, or tuberculosis
• History of osteoporosis or osteoporosis on baseline DXA (expect less than 4% of screened population)84
• Vitamin D deficiency (<10 ng/ml) as we felt it was unethical to withhold supplementation for 12 months in severe deficiency (according to our KPNW survey, this will exclude <2% of population)
• Consuming more than 400 IU of Vitamin D supplementation daily (we felt such doses taken outside of the study design could confound results)
• Current smoker (within the last year)
• Taking medications that affect body weight
• Prior bariatric surgery
• Taking medications or herbal supplements that affect mood (i.e. antidepressants) or menopausal symptoms (i.e. herbal meds) or sleep
• Weighing more than 400 pounds (cannot fit on DEXA scan)
• Not fluent in English or cognitively impaired