Dietary polyunsaturated fatty acids intake, air pollution, and the risk of lung cancer: A prospective study in UK biobank.

BACKGROUND

Epidemiological evidence on the association between specific types of polyunsaturated fatty acids (PUFAs) intake and lung cancer risk is limited. However, whether dietary-specific PUFAs intake can modify the association between air pollutants and incident lung cancer remains unknown.

METHODS

Cox proportional hazard models and restricted cubic spline regression were used to evaluate the associations of omega-3 PUFAs, omega-6 PUFAs and the ratio of omega-6 PUFAs to omega-3 PUFAs intake with lung cancer risk. Furthermore, we evaluated the associations between air pollutants and incident lung cancer, and whether dietary-specific PUFAs intake would modify the relationship using stratification analyses.

RESULTS

This study found significant associations between the risk of lung cancer and omega-3 PUFAs intake (hazard ratio [HR], 0.82; 95 % confidence interval [CI], 0.73-0.93; per 1 g/d), and omega-6 PUFAs intake (HR, 0.98; 95 % CI, 0.96-0.99; per 1 g/d). We did not observe an association between the omega-6 to omega-3 PUFAs intake ratio and incident lung cancer. With regard to air pollution, omega-3 PUFAs intake attenuated the positive relationship between nitrogen oxides (NOx) pollution and lung cancer risk, and an increased incidence of lung cancer was found only in the low omega-3 PUFAs intake group (p < 0.05). Surprisingly, PUFAs intake (regardless of omega-3 PUFAs, omega-6 PUFAs, or in total) reinforced the pro-carcinogenic effects of PM2.5 on lung cancer, and a positive association between PM2.5 pollutants and incident lung cancer was observed only in the high PUFAs groups (p < 0.05).

CONCLUSIONS

Higher dietary omega-3 and omega-6 PUFAs intake was associated with a decreased risk of lung cancer in the study population. As omega-3 PUFAs have different modification effects on NOX and PM2.5 air pollution related lung cancer incidence, precautions should be taken when using omega-3 PUFAs as health-promoting dietary supplements, especially in high PM2.5 burden regions.