Wednesday, April 4, 2018

Wisdom Wednesday: Vitamin D Linked to Metabolic Syndrome in Postmenopausal Women

Postmenopausal women with vitamin D deficiency have greater risk for metabolic syndrome than those with sufficient levels, data from a cross-sectional cohort study suggest. Levels of 25-hydroxyvitamin-D below 20 ng/mL were also linked to a greater likelihood of high triglycerides and low high-density lipoprotein (HDL) cholesterol.

“These results suggest that the maintenance of adequate serum levels of 25(OH)D in postmenopausal women may reduce the risk of developing [metabolic syndrome], a condition that is known to be related to cardiovascular events and mortality in this group,” write Eneida Boteon Schmitt, MD, from Sao Paulo State University’s Botucatu Medical School in Brazil, and colleagues.

The study, published in the January 2018 issue of Maturitas, included 463 women, 45 to 75 years old, who had not menstruated for at least a year, were not taking vitamin D supplements, and had a diagnosis of cardiovascular disease. The researchers measured their total cholesterol, HDL levels, low-density lipoprotein (LDL) levels, triglycerides, glucose, insulin, and 25(OH)D levels.

Vitamin D deficiency was defined as serum 25(OH)D levels below 20ng/mL, whereas levels between 20 and 29 ng/mL were insufficient. Levels of at least 30 ng/mL were considered sufficient. Diagnosis of metabolic syndrome required presence of at least three of five criteria: a waist circumference greater that 88 cm, triglycerides at least 150mg/dL, HDL levels below 50 mg/dL, blood pressure at least 130/85, and glucose at least 100 mg/dL.

Just under a third (32.0%) of the women had sufficient vitamin D levels, and a similar proportion (32.6%) had insufficient levels. The remaining 35.4% were deficient. More than half (57.8%) of the women without sufficient vitamin D (below 30 ng/mL) had metabolic syndrome compared with 39.8% of the women with sufficient vitamin D levels.

After adjustment for age, time since menopause, body mass index, smoking, and physical activity level, women deficient in 25(OH)D had nearly double the odds of metabolic syndrome as those with sufficient levels. Decreasing concentrations of vitamin D correlated with an increase in the number of metabolic syndrome criteria met.

My Take:
In a recent blog, I noted that the optimal levels of vitamin D are 42-100 ng/mL, far above the ranges used for this study. Please note that only a third of the women met the medical sufficient level of 30 ng/mL. This mirrors my clinical experience in testing vitamin D in my patient population.

Evaluating and treating aspects of metabolic syndrome is a cornerstone of my practice. With the possible exception of autoimmune disease, it is my focus with each and every patient.

Bottom Line:
Regardless of age, sex, or physical health, please have your serum 25(OH)D levels checked annually, and more often if you are below 42 ng/mL. It is a simple, inexpensive, non-fasting blood test.

The nutrition board that governs my practice allows me to recommend up to 4,000 IU of vitamin D3 as a daily supplement without laboratory testing to confirm a deficiency. Supplementation above 4,000 IU per day requires laboratory testing or a least planned future testing to monitor serum levels.

Please avoid levels above 4,000 IU without supervision and avoid the 50,000 IU once a week vitamin D supplement at all costs. Liver toxicity is a real consequence of this overdose.

Source: March 28, 2018 National Institutes of Health

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