1. The effects of low dose infusion of atrial natriuretic peptide (ANP) were observed in double-blind, placebo-controlled study in six fluid-loaded volunteers. After baseline observations, hourly increments of 0.4, 2 and 10 pmol min-1 kg-1 were infused with continuous observation of heart rate, blood pressure and cardiac output. Plasma ANP, aldosterone, and catecholamines, and urinary volume and sodium excretion, were estimated at half-hourly intervals. 2. ANP infusion resulted in an increase of 35, 98 and 207% in urinary sodium excretion and of 10, 20 and 71% in urinary volume when compared with placebo. Plasma ANP was markedly elevated above placebo levels only during infusion of 10 pmol of ANP min-1 kg-1. 3. No change in heart rate of blood pressure was noted during the study, but a significant fall in stroke volume index was observed during active treatment. Plasma levels of aldosterone and catecholamines were not significantly different on the 2 treatment days. 4. The potent natriuretic and diuretic effects of this peptide at plasma concentrations not significantly elevated from physiological suggest a hormonal role for ANP in the homoeostasis of salt and water balance.

SUMMARY A study was made of smoking and dietary habits in middle aged Bangladeshi men living in East London to investigate possible causes of the previously described high ischaemic heart disease risk in this group. The results showed that these individuals were 50% more likely to smoke than Caucasians living in the same area, after adjusting for age and social class. More striking, however, was the very high fat intake of over 200 g/day, which is twice the national average and accounted for nearly 60% of total energy intake. Interestingly, much of the dietary fat was from vegetable oil, and the ratio of polyunsaturated to saturated fatty acids exceeded the accepted recommended minimum. Subjects and methods SUBJECTSThe subjects were drawn from the age sex register of a local general practice participating in a heart disease prevention programme. All Caucasian and Bangladeshi men aged between 35 and 69 were invited to attend for a screening examination to include smoking history, weighing, urine testing, and blood pressure measurement. Estimates of the number of cigarettes smoked per day were, however, frequently inconsistent, and thus for the purposes of analysis the fact of current smoking or not was used as being more reliable. DIETARY ENQUIRYConventional dietary survey methods, for example the 24 hour recall4 and the diet interview,5 were inappropriate for studying the Bangladeshi men because of language and cultural barriers. It was therefore decided to study the dietary habits of a small sub sample of these men in depth. Thus the 12 study men were visited at home for a single day. This permitted observation of their wives during preparation and cooking of the food and allowed weighings of the raw ingredients. Further observation of these individuals during the main meals also permitted weighing of the final portion 301

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SUMMARY The role of blood pressure in explaining the increased risk of ischaemic heart disease (IHD) in Bengali immigrants living in the East End of London was studied in a comparative population study. In addition the effect on blood pressure of age, body mass, and duration of stay in the UK was evaluated. The Bengalis had significantly lower mean systolic and diastolic blood pressures though these differences disappeared after adjustment for age and body mass. Both groups, however, showed similar rises of blood pressure with increasing age and body mass. The effect on blood pressure of duration of time spent in the UK by the Bengalis could not be separated from that due to age, given the association between them. It seems unlikely that increasing duration of stay in inner London per se has a hypertensive effect on Bengali immigrants coming from a rural community. Further, the increased IHD risk in this group is not explained, even in part, by an increase in blood pressure.Immigrants from Bangladesh living in the East End of London are reported as having a greater than expected incidence of myocardial infarction.' It is likely that high dietary fat and, in men, cigarette smoking explain part of the increased risk as compared to the indigenous population.2 A third possibility is that elevated blood pressure might be relevant. Thus the environmental change associated with migration from the rural region of Sylhet in Bangladesh to the urbanised and relatively multi-deprived area of inner London might result in a rise in blood pressure, and the latter could be related to duration of stay in the United Kingdom. The objectives of this study were, therefore:1 to compare the blood pressure in Bengali immigrants with that ofthe indigenous population; 2 to compare the effects of age and other possible predictors on blood pressure in the two populations; and 3 to determine the effect of duration of stay in the UK on blood pressure in the Bengalis. Methods SUBJECTSSubjects were drawn from the age-sex register of a local multi-ethnic general practice. All patients aged 35-64 were identified, and attempts were made during the course of a 12 month period to invite them to attend a special screening clinic in the surgery, or to have them screened at the health centre on attendance for another reason. The original population from the age-sex register was 2082, including 1086 Caucasians of UK origin and 655 Bengalis, but the high population mobility in this area resulted in considerable inaccuracy in the age-sex register. Using similar methods to those ofa previous study,3 the best estimate was that 989 European and 312 Bengali patients were available for screening, of whom 617 (63%) Europeans and 155 (50%) Bengalis were screened during the 12 month period. METHODSAll assessments were made by a single observer (EL). The Bengali patients were asked to bring, if necessary, an English speaker with them, though an interpreter was available. Information on age for the Bengalis was verified where possible using official documents thou...