RENAL-CELL CARCINOMA AND THIAZIDE USE - A HISTORICAL, CASE-CONTROL STUDY (CALIFORNIA, USA)

Renal cell carcinoma has been linked to hypertension and antihypertens ive medications. We investigated the association between renal cell ca rcinoma and the use of thiazide in a case-control study of 167 men and 90 women. Subjects were members of the Kaiser Permanente Medical Care Program in northern California (United States) who had taken a multip hasic health check-up from 1964 through 1988 and who were evaluated fo r cancer until the end of 1989. Control subjects received the same che ck-up, were matched by gender, year of check-up, and age at check-up, and had to be in the health plan until the date on which renal cell ca rcinoma was diagnosed. Data on known and potential risk factors, inclu ding hypertension, body mass index (BMI), and smoking status, were col lected from the record of the check-up. Thiazide use was abstracted fr om the medical chart, which was reviewed from the date of the first en try until the date on which the cancer was diagnosed or the equivalent date for control subjects. The mean follow-back to check-up was 11.3 years. Among women, we found a significantly elevated risk of 4.0 (95 percent confidence interval [CI] 1.5-10.8) associated with ever having used thiazide after we adjusted for smoking, BMI, hypertension, and h istory of kidney infection at check-up. We did not find a statisticall y significantly elevated risk in men. Smoking was related to renal cel l carcinoma in men (odds ratio [OR] 2.5, CI = 1.1-5.4) for those who s moked at least one pack per day compared with those who had never smok ed, but was not related in women. We found a statistically nonsignific ant relation between BMI and renal cell carcinoma. After we adjusted f or thiazide use, we did not find that hypertension was a statistically significant risk factor for renal cell carcinoma. Analysis of the dos age of thiazide measured by time since first use, duration of use, num ber of mentions of use in the chart, and an estimate of total grams of exposure did not result in any convincing dose-response relation. The se findings are consistent with a growing body of data linking antihyp ertensive medication with renal cell carcinoma. We are unable to concl ude whether thiazide use or some other characteristic of hypertensive persons taking these medications is responsible for the association.