Hypertension : Epidemiological studies of prevalence, prevention, treatment and prognoses in men and women

Abstract: Background and aim: Hypertension is ranked as the leading risk factor for mortality and the third most common factor leading to disability in the world. Hence, detection, treatment, prevention and control are of high priority. The aim of this thesis was to study the prevalence of both diagnosed hypertension and newly diagnosed high blood pressure (unknown hypertension) and how well diagnosed hypertension is treated in Stockholm County, an urbanized region of Sweden. In addition, we aimed to find factors that might be helpful in the prevention and control of hypertension by studying factors associated with newly diagnosed high blood pressure, and factors associated with hypertension control. Finally, we aimed to study age-adjusted mortality in men and women with different baseline blood pressures during a 26-year follow-up. Material and methods: Two population based samples were used in the studies included in this thesis. One comprised 4232 men and women aged 60years that was used for crosssectional studies, and one comprised 2578 men and women with a 26-year follow-up in the National Cause of Death Register. The participation rate was high (≈80%) in both studies and study participants were thoroughly investigated, making adjustments for many variables possible. Blood pressure was measured on one occasion in both studies. Results: The total prevalence of hypertension (in 60-year-olds) was 62% among men and45% among women. In Swedish-born individuals (n=3327) the prevalence was 61% in men and 44% in women, among Finnish-born individuals (n=327) it was 77% in men and 62% in women, and among non-European immigrants (n=123) the rates were 51% and 36%, respectively. Only 22 % of the men and 33 % of the women with diagnosed hypertension had a blood pressure below 140/90 mmHg. All individuals with diagnosed hypertension and a goal blood pressure had antihypertensive therapy. Both men and women had multiple cardiovascular risk factors in addition to their hypertension. Waist circumference ≥95cm (quintiles 3-5) in men and ≥88.5cm (quintiles 4-5) in women was associated with newly diagnosed high blood pressure. Secondary school was negatively associated in men, OR 0.73 (0.54-0.99), and university education was negatively associated in both men, OR 0.66 (0.52-0.85), and women, OR 0.45 (0.34-0.59). Regular physical activity was negatively associated in women OR 0.77 (61-0.99), and high alcohol consumption (> 30 g/day) was positively associated in men, OR 1.60 (1.22-2.09). Female gender was negatively associated with newly diagnosed high blood pressure, OR 0.50 (0.41-0.61). The 26-year follow-up revealed that the hazard ratio for all-cause mortality in those with very high blood pressure (mmHg, systolic/diastolic), ≥ 160 and/or 95, was 1.93 (1.38-2.70) in men and 2.29 (1.42-3.69) in women. High blood pressure, ≥ 140 and/or 90 but < 160 and 95, and prehypertension ≥ 130 and/or 85 but < 140 and 90 were significant in women but not in men. Hypertension as a risk factor appears to be independent of healthcare needs, a proxy for co-morbidities. Conclusion: High prevalence and poor control of hypertension were found in this Swedish cohort, despite better opportunities for combating hypertension than are available in most parts of the world. Based on the findings in this thesis, prevention of hypertension needs to be gender specific, and should focus on physical exercise to reduce waist circumference in both men and women. Elevated blood pressure should be given just as high priority in patients with co-morbidities as in otherwise healthy individuals. Hypertension should receive more attention in Sweden; the high prevalence and poor control may otherwise lead to premature death, and unnecessary suffering and healthcare costs. Societal changes are needed as well as intensive screening, prevention and antihypertensive therapy.