Effect of Vitamin D and Calcium Supplementation on Cancer Incidence in Older Women: A Randomized Clinical Trial.

What Was Tested

This randomized controlled trial looks at Vitamin D, K2, Magnesium and Zinc.

Who Took Part

According to the abstract, 2303 women were involved.

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

A total of 2303 healthy postmenopausal women 55 years or older were randomized, 1156 to the treatment group and 1147 to the placebo group.

Duration of treatment was 4 years.

How the Study Was Run

In design terms this was a randomized, double-blind and placebo-controlled study.

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.

Neither the women nor the staff measuring them knew who was on Vitamin D, K2, Magnesium and Zinc, so expectations could not easily colour the readings.

A placebo (an inactive look-alike) gave the Vitamin D, K2, Magnesium and Zinc group a baseline to be compared against.

A 4-year, double-blind, placebo-controlled, population-based randomized clinical trial in 31 rural counties (June 24, 2009, to August 26, 2015-the final date of follow-up).

What Was Measured

PubMed files the paper under topics including Calcium, Cholecalciferol, Hypercalcemia, Incidence, Intention to Treat Analysis, Kaplan-Meier Estimate and Kidney Calculi.

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 2303 women.

With several hundred people or more, it is a fairly large study for this kind of research.

Results are reported in around 9 sentences of the abstract; we leave them to the paper itself rather than summarise them.

The publication is from 2017 (JAMA), a journal based in United States.

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