Researchers from the University of South Australia conducted a large study with more than 300,000 participants to analyze the relationship between vitamin D deficiency and mortality. They used a Mendelian randomization technique to study genetic variants that serve as "proxy indicators" for external factors that influence vitamin D levels, such as exposure to sunlight and supplements.
The study, titled "Vitamin D Deficiency Increases Mortality Risk in the UK Biobank" published in the Annals of Internal Medicine, reveals that low vitamin D levels increase mortality risk. However, the randomized clinical trials failed to recruit those with severe vitamin D deficiency likely due to ethical concerns.
Conducting a Nonlinear Mendelian Randomization Analysis
The team used the data from the UK Biobank to perform a nonlinear Mendelian randomization analysis of 3007,601 participants that will assess the genetic evidence for the causal role of vitamin D in mortality, according to an article in Medical Dialogues.
In their study, researchers evaluated measurements of 25-hydroxyvitamin 25(OH)D and other genetic information from the participants. They also listed and analyzed data on all-cause and cause-specific mortality.
The research was a longitudinal study so they did follow-ups with participants for 14 years to see how vitamin D levels influence their mortality risk. Researchers identified 18,700 deaths within that period, wherein they found an L-shaped association between genetically predicted 25(OH)D with all-cause mortality.
Moreso, the authors found that increased vitamin D levels in the body also decreased the risk of death in participants. The effect was more evident in those in the severe deficiency range.
Researchers noted that the prevalence or proportion of how common severe deficiency range from 5% to 50% of the population, which may vary depending on geographical location and population characteristics.
They concluded that the findings of their study support the potential for a notable effect of premature death and the continued need to address and eliminate vitamin D deficiency among communities.
Vitamin D and Health
Vitamin D is a fat-soluble vitamin that is known to help the body absorb and retain critical bone-building elements of calcium and phosphorus, per Harvard T.H. Chan School of Public Health. Previous studies have also shown that vitamin D can reduce cancer cell growth, help fight infections, and reduce inflammation.
The vitamin's role in disease prevention is a popular topic of research that has still no clear answers today about the benefit of taking amounts beyond the RDA. Clinical trials have yet to prove that vitamin D supplements affect a particular disease aside from observational studies that have a strong link to lower rates of certain diseases.
It is best to include vitamin D-rich food in the diet. But there are few foods that are naturally rich in vitamin D3 and usually, they are the flesh of fatty fish and fish liver oil. Although, small amounts are also found in egg yolks, cheese, and beef liver.
Several mushrooms also contain vitamin D2, especially those commercially sold because they are intentionally exposed to high amounts of ultraviolet light.
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