The effect of season and vitamin D supplementation on bone mineral density in healthy women: a double-masked crossover study.

What Was Tested

Researchers studied Vitamin D, K2, Magnesium and Zinc in this randomized controlled trial publication.

The present study was devised to investigate whether a seasonal variation in BMD could be detected in healthy normal subjects, along with associated variations in serum parathyroid hormone (PTH), intestinal calcium absorption and biochemical markers of bone turnover.

A second aim was to investigate whether, if such variations were identified, they could be suppressed by vitamin D supplementation.

Why It Was Studied

Vitamin D status is known to be an important determinant of bone mineral density (BMD).

During the second year the treatment each group received was reversed.

Who Took Part

According to the abstract, 70 volunteers were involved.

The age groups tagged for this paper are adults, middle-aged adults and older adults, women only.

How the Study Was Run

The design is described as randomized, double-blind, placebo-controlled and crossover.

Because people in this Vitamin D, K2, Magnesium and Zinc study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

As a double-blind Vitamin D, K2, Magnesium and Zinc study, the assignments were hidden from both participants and investigators until the end.

The comparison arm used a placebo, so changes seen with Vitamin D, K2, Magnesium and Zinc could be set against what happens without it.

In the crossover set-up each of the volunteers took both Vitamin D, K2, Magnesium and Zinc and the comparison in turn, acting as their own control.

Lumbar spine (L1-L4), left proximal femur and total body BMD were measured by DXA at 3-month intervals.

What Was Measured

Serum 25-hydroxyvitamin D (25-OHD), serum PTH, bone markers (bone-specific ALP (BSAP) and urinary crosslinks (DYPD/creatinine)) and calcium absorption were also measured at each visit.

Topics PubMed links to this paper include Biomarkers, Bone Density, Dietary Supplements, Lumbar Vertebrae, Menopause, Seasons and Vitamin D.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Vitamin D, K2, Magnesium and Zinc in 70 volunteers.

The publication is from 2001 (Osteoporosis international : a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA), a journal based in England.

More context: the Vitamin D, K2, Magnesium and Zinc compound page, all human trials.