Sodium and potassium intakes in a representative population sample: estimation from 24 h urine collections known to be complete in a Cambridgeshire village.

1. A representative sample of eighty men aged 25-44 years from a Cambridgeshire village, each carried out one 24-h urine collection which was analysed for sodium, potassium, creatinine and urea content. The completeness of the collections was verified using oral doses of p-aminobenzoic acid (PABA; the PABA check test). 2. In the seventy-one collections shown to be complete, the average 24 h excretion of Na was 172 mmol and the average 24 h excretion of K was 74 mmol. 3. Fifty-one of these men's wives also made complete 24 h collections. The average content of these was 128 mmol Na and 61 mmol K. 4. Self reports and creatinine index would have identified as incomplete only 29 and 14% respectively of collections so judged by PABA. 5. Average excretion of 150 mmol Na/d was similar to estimated intakes of 140-167 mmol/d from the National Food Survey (Bull & Buss, 1980).