Relationship of urinary sodium and potassium and of urinary sodium/creatinine, potassium/creatinine and sodium/potassium ratios to stomach cancer and cerebrovascular disease mortalities in Japanese women.

To test Joossens's hypothesis that salt is a common cause of both cerebrovascular disease (CVD) and stomach cancer (SC), the standardized mortality ratios (SMRs) of SC and CVD were related to urinary Na and K and urinary Na/creatinine (Cr), K/Cr, and Na/K ratios. Fifty spot urine of females between 40 to 69 years was collected from each of 169 municipalities (88 urban and 81 rural) covering all prefectures in Japan using the filter paper sampling technique in 1985. While the SMR levels of CVD correlated significantly with Na, Na/Cr and Na/K, the SMR levels of SC showed no correlation with Na, K, Na/Cr, K/Cr or Na/K. It was therefore concluded that the geographical distribution of female SMR for SC could not be explained using only the urinary Na excretion as an index of Na intake, and that multiple risk factors and risk reducing factors should be taken into account to explain the distribution.