Logo NHC

Could a Woman’s Lack of Sun Exposure be as Risky as Smoking?

avoiding sun may affect vitamin d levels

Nonsmokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking.

I was somewhat taken aback when reading these results from a study recently published in the Journal of Internal Medicine. While I have always known that some sun exposure is necessary for our bodies to generate the vitamin D we need, it is intriguing to learn of this revelation.

sun exposure - photo

The study referenced is a prospective 20-year follow up of the Melanoma in Southern Sweden cohort. It analyzed sun exposure habits and potential confounding variables of nearly 30,000 women using modern survival statistics. The goal was to explore the differences in main causes of death according to sun exposure.

Subjects who had “active” sun exposure habits “were mainly at a lower risk of cardiovascular disease (CVD) and non-cancer/non-CVD death as compared to those who avoided sun exposure.” Due to their increased survival though, logically the “relative contribution of cancer death increased in these women.”

Interestingly, when smoking was factored in, “even smokers at approximately 60 years of age with the most active sun-exposure habits had a two-year longer life expectancy compared with smokers who avoided sun exposure.”

Yes, we still need to be aware of the fact that sun exposure can lead to increased skin cancer risk. The study did find that the women with regular sun exposure who developed the disease had a better prognosis than those who avoided the sun.

Researchers also noted that sun exposure is especially beneficial for women with more pigmentation, such as African American women, because melanomas are rare for them and it takes more sun exposure to synthesize the same amount of vitamin D as a caucasian person.

This graphic from the study explains some of the results and how benefits went up with the amount of sun exposure.

sun exposure chart and risk

Vitamin D Levels & Cardiovascular Disease

The finding that lack of sun exposure “was a risk factor for all-cause death of the same magnitude as smoking” is a new concept, though lower vitamin D (the sunshine vitamin) levels have already been identified as a risk factor for cardiovascular disease in a growing number of studies. This includes heart attacks, congestive heart failure, peripheral arterial disease and strokes, as well as conditions related to cardiovascular disease like high blood pressure and diabetes, according to JohnsHopkinsMedicine.com.

There are large clinical trials taking place currently and over the next five to eight years that will provide more insight into this relationship and may reveal whether increasing low vitamin D levels could prevent heart attacks.

What Does Vitamin D Have to Do With Sun Exposure?

Our skin has a vitamin D precursor within it. When the sun’s UVB rays make contact with our skin, a conversion process is initiated where this precursor becomes the active form of vitamin D, the type our bodies need. If we avoid the sun, this important process does not happen, and we can face health issues due to this shortfall. Of main concern would be bone, immune and, as mentioned above, cardiovascular health. But, this sun exposure study is resulting in more research, which may directly link the “lack of sun exposure” effects with low vitamin D level effects.

Unfortunately, there are only a handful of foods from which we can obtain vitamin D. These include oily fish like salmon and tuna, certain mushrooms and fortified foods. If you are uncertain about your current vitamin D levels, there is a blood test available through Life Extension – of course you will need to visit a laboratory for the blood draw. Your primary physician can also order one.

Aside from sun exposure and diet, vitamin D supplementation is available in a wide variety of strengths from 400 IU to 50,000 IU. Again, consult your healthcare practitioner for the appropriate dosage for you.

Capsules, Tablets, and Liquid options are commonly available for vitamin D supplements. Here are a variety of strengths:

Vitamin D3 400 IU Pure Encapsulations
Vitamin D3 400 IU, 120 Capsules, Pure Encapsulations
Vitamin-D3 1000 IU & K2 Thorne Research Liquid
Vitamin-D3 1000 IU & K2, 1 Oz, Thorne Research
Vitamin D3 2000 IU Tablets, Metagenics
Vitamin D3 2000 IU, 90 Tablets, Metagenics
Vitamin D3 5000 Capsules, Ortho Molecular
Vitamin D3 5000 Capsules, Ortho Molecular



Are You Getting Enough Vitamin D?

It can be hard to tell if you are getting the vitamin D you need. According to the National Institutes of Health, the recommended daily intake is 600 IU for adult women up to age 71. And according to the Journal of the American Board of Family Medicine, 600 IU may be insufficient. Especially since there are several things that can affect vitamin D levels. These include:

  • Skin pigmentation. The darker a person’s skin, the more UVB exposure required to generate the same amount of vitamin D.
  • Distance from the equator. The further you are from the equator, the less UVB light that actually reaches Earth during winter.
  • Age. The skin of seniors seems to be less efficient at the conversion process when it comes in contact with UVB light.
  • Liver and kidney health. When these key organs are not functioning properly, vitamin D absorption and metabolism can be affected.
  • Air pollution. Vitamin D production can be slowed by poor air quality, as carbon particles from pollutants absorb UVB rays.
  • Sunscreen use. Those who use the recommended amounts of sunscreen are blocking UVB light and, therefore, inhibiting the production of vitamin D in the body.
  • Weight. Some believe that fat tissue absorbs vitamin D and being overweight interferes with its bioavailability.
  • Digestive health. Conditions that affect digestion and the gut can reduce vitamin D absorption.


As you consider the main lifestyle factors that can put you at risk for health issues inactivity, obesity and smoking this study implies that we may be prudent to add “avoiding sun exposure” to the list.

Regular sun exposure can be good for your health and longevity if you’re smart about it.

If you’d like to receive health-related articles like this one directly in your inbox, don’t forget to enter your email address below!