Adherence to a diabetes risk reduction diet (DRRD) was associated with a reduced risk of lung cancer, according to new research published in Frontiers in Oncology.
Lung cancer is the leading cause of all cancer deaths while previous research has suggested specific dietary habits may influence its risk and potentially play a role in its prevention, researchers explained.
The DRRD is composed of 9 dietary variables, including cereal fiber, nuts, coffee, whole fruits, the ratio of polyunsaturated to saturated fat, glycemic index (GI), trans-fat, sugar-sweetened beverages (SSBs)/fruit juices, and red and processed meats. Additional studies have revealed higher DRRD scores had the potential to reduce insulin resistance. Authors hypothesized this could be due to “the activation of insulin-like growth factor-1, stimulating of the Ras signaling pathway, local angiogenesis or growth promotion via insulin receptors present on lung cancer cells.”
To conduct the current study, data from 98,159 individuals enrolled in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial were assessed. The study was originally carried out at 10 US centers between 1993 and 2001 among men and women aged 55 to 74 years. The intervention group (n = 50,316 ) received certain screening tests while the control group (n = 47,843) received usual care; all participants completed questionnaires (baseline questionnaire and diet history questionnaire [DHQ]) and were followed-up with until 2009.
“DHQ was used to collect dietary information, including alcohol intake, total energy intake, and intake of food or nutrients in diet to calculate DRRD score,” authors explained. Participants completed the DHQ at an average 3 years following randomization.
Based on DRRD score, individuals were divided into quartiles; the mean (SD) participant age was 65.5 (5.73) years and the mean follow-up time was 8.83 (1.96) years.
- Mean (SD) score of DRRD was 26.82 (5.19), and ranged from 20.47 (2.3) to 33.65 (2.42) from the lowest quartile to the highest quartile, inferring the possibility of highest through the lowest risk of type 2 diabetes
- Calculated hazard ratios (HRs) showed there was a trend that higher quartile indicated lower risk of lung cancer after adjusting for covariates (HR quartile 4 vs quartile 1, 0.85; 95% CI, 0.73-0.98; P for trend = .036)
- The inverse trend between higher DRRD score and the risk of squamous cell carcinoma was more evident (HR quartile 4 vs quartile 1, 0.50; 95% CI, 0.34-0.73; P for trend = .002)
- The inverse association between DRRD score and the incidence of lung cancer was more pronounced in participants who had a clear family history of lung cancer (P for interaction = .016)
Those in the lowest quartile tended to be younger, male, White, married, and have a higher body mass index. More non-smokers and non-drinkers were in the highest quartile compared with the lowest.
Past research has also shown that those with diabetes are more likely to develop cancers with data suggesting hyperinsulinemia and hyperglycemia may accelerate the biological aging process.
“Namely, all the component parts of DRRD are closely related to chronic inflammation, which is also involved in tumorigenesis,” authors added. “We hypothesize the inverse association between DRRD score and the incidence of lung cancer is possibly because of the ease of chronic inflammation, hyperinsulinemia, and insulin resistance.”
Although a strong inverse association was seen between DRRD score and squamous cell carcinoma incidence, a similar link was not seen with adenocarcinoma, large cell carcinoma, or small cell carcinoma incidence, prompting authors to call for more research on this finding.
Further research is also warranted to investigate whether the association between DRRD score and lung cancer risk is related to gene regulation.
“Because smoking increases the level of inflammation in the human body and thus raises the risk of lung cancer, the inverse association between DRRD and lung cancer might be more evident in smokers since adherence to DRRD indicated the alleviation of inflammation,” researchers said.
The potential for dietary habits to change throughout the follow-up period marks a limitation to this study and more research is needed to confirm the association between DRRD score and lung cancer risk.
“People are encouraged to have more cereal fiber, nuts, coffee, fruits, diet with higher ratio of polyunsaturated to saturated fat, which indicates higher DRRD score; but have less intake of high [glycemic index] diet, trans-fat, [sugar sweetened beverages]/fruit juices, and red and processed meats, which indicates a lower DRRD score,” authors concluded.
Zhang Y, Zhong G, Zhu M, Chen L, Wan H, and Luo F. Association between diabetes risk reduction diet and lung cancer risk in 98,159 participants: results from a prospective study. Front Oncol. Published online April 28, 2022. doi:10.3389/fonc.2022.855101