Insulin resistance and risk of renal cell cancer: a case-control study.
OBJECTIVE
Obesity and diabetes are considered risk factors for Renal Cell Carcinoma (RCC). We aimed to explore whether insulin resistance (IR) plays an independent role in the development of RCC.


METHODS
In a hospital-based case-control study, we analyzed serum glucose, insulin, leptin and adiponectin levels among 60 incident RCC patients and 236 age- and gender-matched healthy controls. We assessed insulin resistance according to insulin levels, alone or controlled for diabetes mellitus (DM). An alternative measure of insulin resistance, such as the Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) index, was also assessed with and without controlling for history of DM. We used logistic regression to estimate odds ratios (ORs) adjusted for possible confounders.


RESULTS
The positive association of DM and waist to hip ratio as a measure of obesity with RCC was evident in the data set. Insulin levels controlled or not controlled for DM, however, were inversely associated with the risk for RCC; notably, an approximately 40% higher risk was observed in the 1st tertile when compared with the 2nd and 3rd tertile levels of insulin resistance. Similar results were obtained when HOMA-IR was alternatively used. The inverse associations persisted and were even strengthened after controlling for potential confounding factors in multivariate analyses.


CONCLUSIONS
Our curdata suggest that insulin resistance may be inversely associated with RCC risk, independently of obesity, DM, lifestyle and hormonal confounding variables. Given the close interconnections among metabolic, inflammatory and immune pathways in RCC causation, it is difficult to infer which process actually initiates a pathologic cascade. The findings should be considered as preliminary data that need to be further confirmed in more appropriate study designs.
Department of Hygiene, Epidemiology and Medical Statistics, Athens University Medical School, Athens, Greece.
Themistoklis N
TN
Spyridopoulos
Nick
N
Dessypris
Antonis G
AG
Antoniadis
Spyros
S
Gialamas
Constantine N
CN
Antonopoulos
Konstantina
K
Katsifoti
Hans-Olov
HO
Adami
George P
GP
Chrousos
Eleni Th
ET
Petridou
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000097:blood / Q000209:etiology*; D016022:Case-Control Studies; D048909:Diabetes Complications; D005260:Female; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009765:Obesity / Q000150:complications*; D016017:Odds Ratio; D012307:Risk Factors
D007328:Insulin