Study population The 2010 Brazilian census indicated that 29,192 Matão inhabitants were ≥ 40 years old, representing 38% of the total population. Considering a population of 41,400 covered by FHS, 38% of >40-year-old subjects represent a study population of about 15,000 subjects. The reason to include a population aged ≥ 40 years is justified by the fact that the prevalence of hypertension is almost 20% among subjects 35 to 44 years of age.