SUMMARY A study of the prevalence of hypertension was undertaken among workers in 10 subsectors of the economy in Sao Paulo, a major urban-industrial area of Brazil. Included in the study were 5500 subjects 15-65 years of age, employed in 57 randomly selected firms. Hypertension rates (DBP ^ 90 mm Hg) were higher among males up to 44 years of age. There was a decreasing gradient from mild to moderate and severe forms in all groups. Severity tended to increase with age in all groups. Black males showed higher rates than whites (29.2% vs 16.7%, p < 0.05), the excess being partially accounted for by moderate and severe forms (40% vs 20%). Subjects who overworked showed a trend toward higher hypertension rates. Higher rates in four subsectors (metallurgy, finance, transport, and journalism), aside from the distribution of known risk factors and job selection, may reflect a variety of work-related stressors. 1 " 4 In most developed countries hypertension and associated diseases have been acknowledged as major public health concerns. In underdeveloped countries, however, the issue is much less clear. For a long time, health and disease patterns in underdeveloped countries have been considered to be altogether different from those prevailing in developed societies. Evidence has accumulated in recent years, however, that shows at least in some areas of the so-called "third world" a mixed pattern of disease characterized by disorders considered more prevalent among urban industrial populations than in "traditional" societies.'The transition from traditional to industrial societies is a complex process involving profound social and economic changes that, in turn influence health and disease patterns of the members of society. In urban industrial societies, entry into the job market, qualitative aspects of work (time pressured, hierarchically controlled, competitive) as well as the quantity of work, have been argued to be critical events regarding hypertension. 6 The objectives of the present study were to: 1) estimate the prevalence of hypertension among workers in selected economic activities of a highly urbanized area of the third world, the Metropolitan area of Sao Paulo; 2) provide descriptive data on the epidemiology of hypertension in that population; and 3) set up baseline data for testing hypotheses relating to work-related factors associated with hypertension. MethodologySubjects from 10 subsectors of the economy were studied. In the secondary sector (industry), the following subsectors were selected: textile, metallurgy, housing, and automobile construction. In the tertiary sector (trade and services) the selected subsectors were the following: trade (wholesale, retail), insurance, loans and finance, transportation, advertising and journalism, teaching, liberal arts professionals.In Brazil, a federal law, known as the "Law of the Two Thirds," makes it mandatory for each firm to report annually to the Ministry of Labour the number

SUMMARY Previous analysis based on data derived from a prevalence study of hypertension among workers in different economic activities in the Greater Metropolitan Area of Sao Paulo, Brazil, have shown separate effects of biologic and social attributes on diastolic blood pressure levels (DBP). The present paper explores joint effects of sociodemographic, anthropometric, and behavioral characteristics on blood pressure levels. For that purpose, the Morgan-Sonquist procedure on interaction effects in the prediction of DBP levels was used. Six independent variables emerged as predictors: age, Quetelet index, occupation, schooling years, subsector of the economy, and smoking. Very young and lean women who were also smokers had the lowest mean DBP levels (66.1 mm Hg). Young, overweight women without college education showed intermediate levels (71.5 mm Hg). Highest levels were found among older women in production-linked occupations engaged in transportation and metallurgy activities (89.5 mm Hg). The study suggests that the potential role of work-related characteristics on blood pressure levels is greatest among older women. This assumption, however, has raised methodological issues regarding analytical procedures and interpretation of results. Refinement and elaboration of associations between factors not only need to take into account separate or additive effects but also must try to capture potentially fruitful interconnections.A prevalence study of hypertension undertaken among workers in 10 subsectors of the economy in Sao Paulo, Brazil, estimated the prevalence of the condition in a highly urbanized and industrialized metropolitan area of the Third World. The study also provided descriptive data on the epidemiology of hypertension in that population, having shown separate effects of certain attributes on blood pressure levels.In the present paper, the joint effects of biological and social dimensions on blood pressure levels are explored by means of identifying internally homo- genous subgroups of subjects that differ in respect to blood pressure levels. These subgroups represent combinations of subclasses of biological and social characteristics. Methodology Study PopulationThe study population was composed of subjects in 10 subsectors of the economy. In the industrial sector, the following subsectors were selected: textile, metallurgy, housing and automobile construction. In the trade and service sector, the following were selected: trade, insurance, loans and finance, transportation. In the liberal art professions advertising, journalism, and teaching were included.A two-stage sampling procedure was used. The sample size totaled 5500 workers -4013 men and 1457 women aged 15-65 years from 57 firms. Detailed study design and methodology are described elsewhere.1 This report presents results for the female group in the sample. VariablesExplanatory variables introduced in the analysis included sets of demographic (age, ethnicity, parity, nativity, family), anthropometric (Quetelet index), social class indicators...

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