Individuals with vitamin D deficiency may be at greater risk of interstitial lung disease, a rare disease that causes scarring of the lungs.
In a new study, scientists at the Johns Hopkins University School of Medicine have found that individuals with lower than normal blood levels of vitamin D have an increased risk of subclinical interstitial lung disease.
Vitamin D plays a key role in helping the body absorb calcium, and is also an important nutrient for the nervous, immune, and muscle systems. Human skin produces vitamin D through a process known as photolysis when it absorbs ultraviolet B (UVB) rays, and the body’s ability to produce the vitamin is determined by season, time of day, latitude, altitude, air pollution, skin pigmentation, sunscreen use, passing through glass and plastic, and aging. As dietary sources of vitamin D are limited, skin exposure to sunlight is the best source of the vitamin, along with supplements.
Researchers have linked vitamin D deficiency to a range of health issues — including osteoporosis, diabetes, and high blood pressure – and are still discovering how the vitamin is used within various tissues in the body. In a new study published on June 19, 2018, in The Journal of Nutrition, researchers found that low vitamin D is associated with interstitial lung disease (ILD), a rare disease marked by scarring and inflammation of the lungs.
There are about 200,000 cases of ILD in the United States each year. The disorder can occur from long-term exposure to dust or other air particles, and can appear as black lung disease in coal miners who have breathed in coal dust or as farmer’s lung in farmworkers inhaling dust. ILD can also occur in welders who have inhaled welding fumes and individuals who have breathed in asbestos. Over time, these particles can scar the lungs, inhibiting the ability to breathe and receive enough oxygen into the blood.
For the study, the researchers used data collected over a 10-year period from 6,302 participants enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA). All participants had baseline serum vitamin D concentrations and computed tomography (CT) scans of their hearts, which offered a partial view of the lungs. Participants with vitamin D levels in the blood of less than 20 nanograms per milliliter were considered vitamin D deficient; those with 20 to 30 nanograms per milliliter were considered to have intermediate levels of the vitamin and those with 30 nanograms per milliliter or more were reported to have recommended levels. At 10 years into the study, 2,688 participants received full CT scans of the lungs, which were analyzed for the presence of scar tissue and other damage.
After adjusting for age and lifestyle risk factors of lung disease—including current smoking status and history of smoking, physical inactivity, obesity, high blood pressure, high cholesterol, and diabetes–the researchers found that participants with vitamin D deficiency had larger areas of lung tissue damage. Overall, participants with deficient or intermediate vitamin D levels were 50% to 60% more likely to have early signs of ILD, when compared with participants who had recommended levels.
In an interview with Rare Disease Report®, study author Erin Michos, MD, MHS, said that the study did not determine if vitamin D supplementation could reverse the signs of ILD. “Our study was not designed to prove a cause and effect,” he explained. “We just found an association of vitamin D deficiency with these early signs of interstitial lung disease. This was a new association that we found which suggests correcting vitamin D deficiency with treatment may be important for preventing ILD, but we just don’t know that yet.”
Dr Michos noted that use of sunscreen, covered manner of dress, and darker skin pigmentation can all contribute to vitamin D deficiency. “Nevertheless, skin cancer is an important outcome to prevent,” he said. “I still recommend sunscreen, protective clothing, and avoiding prolonged sun exposure. You only need exposure to sunlight for 5 to 10 minutes to arms and legs during peak UVB (summer) exposure for the skin to synthesize about 3000 IU of vitamin D3.”