Annually, more than 1 million people worldwide die from lung cancer, a disease that has a higher mortality rate than any other cancer type.1 Although smoking is a direct contributor to this disease, especially in developing countries where smoking cessation programs are nascent or nonexistent, there is an increase in the number of nonsmokers who are diagnosed with lung cancer each year.1  

While it is challenging to identify exactly which elements, aside from smoking, lead to lung cancer, after a lifetime of breathing in various spaces and places, researchers have been able to identify a few elements with certainty. Passive smoke, radon gas and air pollution, among other environmental contaminants,  have been cited as top carcinogens that can lead to lung cancer, according to Michael Thun, MD, American Cancer Society (ACS) Vice President of Epidemiology and Surveillance.2

In addition, genetics in combination with other environmental factors play a role. For example, cooking oil fumes, fuel smoke, and passive smoking may increase the risk of lung adenocarcinomas in Chinese female nonsmokers who carry p53 or MDM2 mutant alleles, according to an article in the Asian Pacific Journal of Cancer Prevention.3

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Perhaps genes and environmental exposure to certain carcinogens may also explain why some patients who smoke are diagnosed at a young age, while other life-time smokers are never diagnosed with lung cancer. For instance, my maternal grandmother, a smoker, died of lung cancer in her early 40s, while her sister, who also smoked heavily and never quit, lived well into her 80s. This 40-year discrepancy is curious because of the time it usually takes for lung cancer to develop in smokers.

Otis Brawley, MD, Chief Medical Officer of the ACS, wrote that people who quit by middle-age benefit greatly because lung cancer can take 30 to 50 years from the onset of smoking to a diagnosis of cancer and potential death.4 The obvious answer for smokers to reduce risk is to quit smoking. So the question medical professionals may be wondering is: how can nonsmokers also reduce their risk of developing lung cancer?

An interesting study published in early 2013 looked at the association of calcium intake by nonsmokers to potentially offset the risk of lung cancer. The Shanghai Women’s Health Study reviewed the diets of 71,267 nonsmoking women during the course of 11 years. During this time, 428 women were diagnosed with lung cancer. The women in this population-based study were evaluated through a food frequency questionnaire on the association of intakes of calcium and related minerals. The median intakes were calcium 441 mg, magnesium 266 mg, and phosphorus 935 mg.5

According to the researchers, calcium and phosphorus supplementation as well as the calcium-to-magnesium (Ca:Mg) ratio were inversely associated with lung cancer risk. The hazard ratios for the highest compared with the lowest quartile were 0.66 (95% CI: 0.48-0.91) for calcium, 0.55 (95% CI: 0.36-0.85) for phosphorus, and 0.62 (95% CI: 0.47-0.82) for the Ca:Mg ratio.5  

The study concludes that calcium supplementation may play a role in lung cancer prevention in female nonsmokers who have a low amount of dairy in their diet.

Engaging a nutritionist as part of the oncology team may also benefit patients to determine the best course of action for diet-related risk reduction strategies.

References

  1. Jemal A, Bray F, Center MM, et al. Global cancer statistics. CA Cancer J Clin. 2011;61(2):69-90.
  2. American Cancer Society. Lung cancer also affects nonsmokers. http://www.cancer.org/cancer/news/lung-cancer-also-affects-nonsmokers. Accessed November 4, 2013.
  3. Ren YW, Yin ZH, Wan Y, et al. P53 Arg72Pro and MDM2 SNP309 polymorphisms cooperate to increase lung adenocarcinoma risk in Chinese female non-smokers: a case control study. Asian Pac J Cancer Prev. 2013;14(9):5415-5420.
  4. Brawley O. Avoidable cancer deaths globally. CA Cancer J Clin. 2011;61(2):67-68.
  5. Takata Y, Shu XO, Yang G, et al. Calcium intake and lung cancer risk among female nonsmokers: a report from the Shanghai Women’s Health Study. Cancer Epidemiol Biomarkers Prev. 2013;22(1):50-577.

Topics:

Lung Cancer Smoking