Aims
To explore the relationship between fatty acid lipophilic index (LI) of erythrocyte membrane and oral cancer risk, as well as to evaluate the possibility of LI acting as a mediator of the association between body mass index (BMI) and oral cancer.
Method
In a case-control study from China, 23 fatty acids (FAs) of the erythrocyte membrane were measured using gas chromatography in 380 oral cancer patients and 387 control subjects. The LI was calculated based on FA proportion and FA melting points. The association of BMI and erythrocyte LI with oral cancer risk was analyzed using logistic regression. Mediation effect of the LI on the association between BMI and oral cancer risk was evaluated using mediation analysis.
Results
Among the control group, 46.0% of them were overweight or obese, which was significantly higher than that of oral cancer patients (29.5%). Significant differences of erythrocyte membrane saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs) were observed between the patient and control group. The proportion of C18:1 n-9 from the MUFAs family increased in oral cancer patients (12.67%) compared with control (12.21%). While the total proportion of n-3 PUFAs decreased in oral cancer patients compared with control, with C20:5 n-3 decreased from 0.66–0.47%, and C22:6 n-3 decreased from 5.82–4.86%. The LI was lower in the control participant (M = 27.6, IQR: 27.3–27.9) than that of the oral cancer patients (M = 28.2, IQR: 27.9–28.5). BMI was inversely associated with oral cancer risk with a fully adjusted ORs of 0.59 (95% CI: 0.43–0.83), while LI was positively associated with oral cancer risk with a fully adjusted ORs of 1.99 (95% CI:1.36–2.94). LI explained 7% of the variance in the relationship between BMI and oral cancer risk.
Conclusions
Distribution of the FA profile in erythrocyte membranes differed between the oral cancer patients and control group. The LI derived from the profile of FAs was positively associated with the risk of oral cancer, and the associations between BMI and oral cancer risk could be explained, at least in part, by LI.