Descrição
Introduction: Physical activity (PA) and a ‘healthy’ diet are believed to have a beneficial role in
both prevention and treatment of high blood pressure (BP) (Forman et al., 2009).
However, the magnitude of the relationship of PA and dietary patterns with hypertension
incidence remains to be clarified, especially in European populations with high
prevalence of CVD, as in Portugal.
The purpose of the present study was to examine longitudinally the role of PA
(type and intensity) and a nutrient based DASH dietary pattern and food intake in
hypertension incidence, in an urban sample of Portuguese adults, aged ≥40 years. Methods: As part of the EPIPorto cohort study, comprising 2485 adults, residents in Porto,
Portugal, we included 549 subjects aged ≥40 years, at risk of developing hypertension. BP
measurements were obtained twice (1999–2003 and 2005–2008), with a median interval
of 3.8 years. Hypertension was defined as systolic BP ≥ 140mmHg and/or diastolic BP ≥
90mmHg, and/or if the subjects were under anti-hypertensive therapy (Chobanian et al.,
2003).
Validated questionnaires were used to assess usual PA (Camões et al., 2010) and
dietary intake (Lopes et al., 2000), during the previous year. PA was estimated by
multiplying an average of the metabolic equivalent (MET) by the self-reported time spent
on different activities (sleep, work, housework and leisure-time activities). Individuals were
classified into different types of PA, namely occupational and leisure-time, using the METs
unit as a multiple of resting metabolic rate (MET-h/day). Physical activity level (PAL) was
also calculated (PAL=Total energy expenditure/resting metabolic rate).
Dietary intake was estimated based on a semi-quantitative food frequency
questionnaire, comprising 82 food items, beverage categories and a frequency section. A
DASH score based on prior nutrient goals was created to assess adherence to the DASH
diet (Table 1). We also analyzed the individual effect of some nutrients included in the
DASH score (potassium and sodium), as well as fruit, vegetables and pulses.
Poisson regression was used to calculate the incident rate ratios (IRRs) and
respective 95% confidence intervals (95% CIs). Results: In our population, the crude incidence rate (95% confidence interval (CI)) per 100
person-years of hypertension was 6.23 (5.26–7.20).
After adjustment for gender, age, education, body mass index, physical activity
level and total energy intake (baseline), an inverse, though not significant, association
was found across increasing tertiles of leisure-time PA, IRR (95% CI): 1 (reference);
0.77 (0.51–1.16); and 0.74 (0.48–1.11) (Table 2).
No significant associations between the DASH score and hypertension incidence
were observed. However, a decrease of hypertension risk [IRR (95%CI)] by increasing
tertiles of potassium intake (<1630.4; 1630.4-1863.0; >1863.0 mg/1000kcal for women;
<1470.5; 1470.5-1657.2; >1657.2 mg/1000kcal for men) was observed: 1 (ref.); 0.81
(0.56-1.18); 0.63 (0.42-0.94) (p for trend, 0.024) (Table 3).
Additionally, in multivariate analysis, a significantly inverse association between
the consumption of fruits/vegetables/pulses and hypertension incidence was found
(upper vs. first tertile: IRR=0.61 (0.40–0.93), p for trend=0.024) (Table 3). Conclusions: In Portuguese adults, higher intakes of potassium and fruits/vegetables pulses, and also higher levels of leisure-time PA seemed to be associated with a lower risk of hypertension. Primary public health interventions regarding behavioural risk factors would be valuable, particularly in a context of high mortality due to stroke events, as in Portugal.