Metabolic syndrome carries increased risk of lung cancer

Individuals with metabolic syndrome (MetS) have a heightened risk of incident lung cancer, with the risk increase especially pronounced in those with a higher number of metabolic abnormalities and in women, according to a study.

For the study, researchers used data from the UK Biobank and included 331,877 participants (mean age 56.3 years, 53 percent women). The association between MetS and incident lung cancer was estimated using multivariable Cox regression models.

A total of 77,173 participants had MetS at baseline, with a prevalence of 23.3 percent. Most of them (82.6 percent) had at least one metabolic abnormality. Compared with participants without MetS, those who had the condition were older and had lower socioeconomic status and were more likely to be men, non-White, smokers, exposed to second-hand smoking, and have a family history of lung cancer, chronic obstructive chronic disease, and obesity.

Over a median follow-up of 10.9 years, 2,425 participants received a diagnosis of lung cancer as the primary site, with 1,001 cases of adenocarcinoma, 503 cases of squamous cell carcinoma, 26 cases of large cell carcinoma, and 246 cases of small cell carcinoma.

MetS was associated with an elevated risk of overall lung cancer (hazard ratio [HR], 1.21, 95 percent confidence interval [CI], 1.09–1.33), adenocarcinoma (HR, 1.28, 95 percent CI, 1.10–1.50), and squamous cell carcinoma (HR, 1.16, 95 percent CI, 0.94–1.44).

The MetS-associated increase in lung cancer rose further with the number of metabolic abnormalities, ranging from 11 percent to about 40–50 percent for participants with one to five disorders. Positive associations with lung cancer were seen for low high-density lipoprotein cholesterol (HDL-C), elevated waist circumference, and hyperglycaemia.

Of note, the association between MetS and lung cancer was stronger in women (p=0.031) and pronounced among smokers, although the modification effect of smoking was not significant. A nonlinear association was observed between lung cancer and HDL-C, waist circumference, and glycated haemoglobin.

The findings highlight the importance of considering metabolic status and markers in the primary prevention of lung cancer and in the selection of high-risk populations for lung cancer screening.