A recent study published by the Archives of Osteoporosis Journal found that air pollution is an independent risk factor for vitamin D deficiency.
Air pollution refers to a combination of small solid and gas matter that is detrimental to the health of humans and the planet. Causes of air pollution include motor vehicle emissions, chemical and metal toxins in the environment and emissions from industrial plants. In the US, air pollution has fallen dramatically since the 1960s
Air pollution contributes to the onset of allergies, chronic diseases and mortality in humans. Additionally, pollution creates a barrier that decreases the ability of UVB rays to reach the earth’s atmosphere, potentially reducing the body’s capacity to produce vitamin D naturally.
Vitamin D plays numerous roles, one is the body’s ability to maintain a healthy inflammatory and immune response, two key components in disease prevention. In fact, vitamin D deficiency is linked with the development of at least 45 chronic diseases.
Childhood vitamin D deficiency not only negatively impacts bone health, but has been linked with developmental delays and short stature. Additionally, since individuals lose the ability to improve bone mineral density (BMD) by the age of 30, it is important to address modifiable risk factors for impaired bone health early on in life.
Therefore, researchers recently aimed to determine whether a relationship exists between air pollution, vitamin D deficiency and bone turnover among adolescents. The study compared ambient air pollution and bone turnover to the prevalence of vitamin D deficiency among 325 middle school and high school aged students in regions of Tehran, Iran in areas of the city with and without pollution.
The researchers obtained data on air pollution from the different areas, which were divided into polluted and unpolluted regions based on the air quality index (AQI). The AQI is used by government agencies to alert the public on the amount of pollution is or is forecasted to be. A higher number indicates a greater degree of pollution. The participants had blood work taken in order to evaluate markers for bone health, including but not limited to calcium, phosphorus, parathyroid hormone (PTH) and 25(OH)D status.
Here is what the researchers discovered:
- A total of 52.9% of students were vitamin D deficient, which was defined as levels < 20 ng/ml).
- On average, vitamin D levels were about 12 ng/ml lower in polluted areas compared to non-polluted areas (p = 0.0001).
- After adjusting for confounding variables, air pollution was associated with vitamin D deficiency (p < 0.01) and bone turnover (p < 0.04).
- Calcium intake of greater than 5,000 mg/week provided a protective effect on air pollution related bone turnover.
The researchers concluded,
“Air pollution is a chief factor determining the amount of solar UVB that reaches the earth’s surface. Thus, atmospheric pollution may play a significant independent role in the development of vitamin D deficiency.”
We were surprised at the magnitude of the effect: about 20 ng/ml in polluted areas and 34 ng/ml in non-polluted areas. Another remarkable finding was the difference between boys and girls, 34 and 25 ng/ml, respectfully. This finding is likely due to the cultural attire commonly worn by girls when they reach this age.
Sturges, M. & Cannell, JJ. Air pollution linked to vitamin D deficiency among adolescents. The Vitamin D Council Blog & Newsletter, 4/2017.