More Reports on Higher Death
Risk From Low Vitamin D Levels
Low levels of vitamin D may increase the risk of dying from
all causes by 150 per cent, suggests a study with over 700 elderly
Women with blood levels of the vitamin lower than 15.3 nanograms
per millilitre were more likely to die from causes such as heart
disease and cancer, than women with higher levels (above 27 ng/ml),
according to findings published in Nutrition Research.
The present findings from this population-based cohort
of ageing are consistent with the association between low serum
25(OH)D and mortality that has been described in [
general population, wrote the researchers, led by Richard
Semba from the Johns Hopkins University.
In addition, a recent meta-analysis suggested that vitamin
D supplementation was associated with decreased mortality,
The researchers noted that several biologic mechanisms could
explain a causal relationship between vitamin D deficiency and
mortality, with the vitamins active form (1,25-dihydroxyvitamin
D) linked to a range of effects including control of inflammatory
compounds, regulating immune health and blood pressure, or reducing
The role that vitamin D plays in different tissues may
account for the associations between vitamin D deficiency and
cardiovascular disease, cancer, and mortality, they said.
The general population study used data from 13,331 men and women
participating in the Third National Health and Nutritional Examination
Survey (NHANES III). The results of the study grabbed headlines
around the world when published last year in the Archives of Internal
The new study looked at vitamin D levels, in the form of 25-
hydroxyvitamin D (25(OH)D), the non-active 'storage' form, in
714 community-dwelling women, aged between 70 and 79 years, participating
in the Women's Health and Aging Studies I and II.
The Johns Hopkins researchers worked in collaboration with scientists
from Wake Forest University, National Institute on Aging, University
of Pennsylvania, and Columbia University.
During 6 years of follow-up, 100 of the 714 women died with data
showing that the main causes of death included cardiovascular
disease (36 per cent), respiratory disease (18 per cent), cancer
(15 per cent), and other causes (27 per cent), state the researchers.
When the researchers divided women into four groups (quartiles)
according to their 25(OH)D levels, the proportion of women who
died in during those 6 years in each quartile (from lowest to
highest) was 19, 13,15, and 8.1 per cent, said the researchers.
Increasing blood levels of vitamin D were linked to increasing
survival rates, with women with the lowest average 25(OH)D levels
having significantly worse survival than women with
the highest average levels of 25(OH)D.
Controlled clinical trials are needed to determine whether
vitamin D supplementation will improve health outcomes such as
cardiovascular disease and mortality in older adults who have
insufficient levels of vitamin D, concluded the researchers.
Vitamin D refers to two biologically inactive precursors - D3,
also known as cholecalciferol, and D2, also known as ergocalciferol.
The former, produced in the skin on exposure to UVB radiation
(290 to 320 nm), is said to be more bioactive.
While our bodies do manufacture vitamin D on exposure to sunshine,
the levels in some northern countries are so weak during the winter
months that our body makes no vitamin D at all, meaning that dietary
supplements and fortified foods are seen by many as the best way
to boost intakes of vitamin D.
In adults, it is said vitamin D deficiency may precipitate or
exacerbate osteopenia, osteoporosis, muscle weakness, fractures,
common cancers, autoimmune diseases, infectious diseases and cardiovascular
diseases. There is also some evidence that the vitamin may reduce
the incidence of several types of cancer and type-1 diabetes.
Source: Nutrition Research