SEASONAL-VARIATION IN THE INCIDENCE OF END-STAGE RENAL-DISEASE

The effect of ambient temperature (AMT) on the incidence of end-stage renal disease (ESRD) was examined in Okinawa, Japan, where there is a distinct seasonal variation in monthly AMT but constant intradiurnal t emperature change throughout a year. Arbitral continuous and cyclic fu nctions were examined using Fourier analysis and calculation of the cr oss-correlation coefficient. The calendar month of the start of chroni c dialysis was regarded as the time of onset of ESRD. A total of 1,982 patients, 824 females and 1,158 males, was registered with ESRD betwe en 1971 and 1990. The normalized monthly number of new ESRD patients, divided by days of each month, was smallest in August, n = 4.06, and l argest in January, n = 6.45, and this pattern was well reproduced by t he Fourier synthesized value. The cross-correlation coefficient showed that monthly mean AMT and the normalized number of ESRD patients corr elated best with 6 months lag time. Taken together, our results showed that there was strong correlation between the normalized number of ES RD patients and AMT. Uremic symptoms leading to initiate dialysis, suc h as congestive heart failure, may be aggravated in lower AMT. We spec ulated a role of an inverse relation between AMT and the sympathetic n erve function. The public health implications of these findings warran t their further investigation.