[Primary prevention of hypertension in the general population. The Lyon Action for the Prevention of Hypertension and Atherosclerosis].
UNLABELLED: The aim of ALPHA (1976-1982) was to realize an action of cardiovascular prevention in a professional population, by combining a) an education of the general population and b) an individual managing of the high risk people. The "Study" (S) population originated from Lyon; the "Reference" (R) population originated from two smaller cities. There was no randomization. The plan of the study included: A baseline cross study, dealing respectively with 9,598 and 9,558 subjects in S and R; The educational intervention, aiming chiefly at reducing caloric and sodium intakes, and at increasing the potassium intake; The evaluation was done after five years, by re-examining the subjects seen at the baseline study and still present in the enterprises. Mainly because of the economic crisis, the re-examination rates were only about 45%. RESULTS: at the baseline, BP's were not significantly different: 137/77 S vs 132/75 R for men, and 129/74 S vs 126/73 R for women. The final comparisons about primary prevention of hypertension were computed after adjustment for age and sex, after exclusion of the subjects who were hypertensive at baseline. The knowledges about hygiene were significantly but moderately better in S. The urinary Na/K and Na/Creatinine ratios did not differ significantly. The alcohol intake was lower in S (p less than 0.001). The incidence of HT was greater in S (p less than 0.001). The means of the individual variations of systolic and diastolic BP were computed: the adjusted differences S-R were respectively + 1.53 and 2.19 mmHg for systolic and diastolic (p less than 0.001 for both). CONCLUSION: the feasibility of the intervention was moderate. The failure to demonstrate any prevention of HT might indicate that the hypothesis was wrong, and/or that the methodology was inadequate.