ABSTRACT
Objective There are no community based, longitudinal, intra individual epidemiological studies on effect of weather and season on blood pressure (BP). We evaluated the effect of season and temperature on prevalence and epidemiology of BP in tropical climate. Methods and results It was a longitudinal cross sectional survey of rural and urban subjects in their native surroundings. BP was measured in four different seasons in same subjects. A total of 978 subjects (452 rural and 521 urban) were included in the current analysis. Demographic characteristics such as age, gender, education, occupational based physical activity and body mass index (BMI) were recorded. Mean BP, both systolic and diastolic were significantly higher in winter season as compared to summer season. Mean difference between winter and summer was 9.01 (95% CI: 7.74–10.28, p < 0.001) in systolic BP and 5.61 (95% CI: 4.75–6.47, p < 0.001) in diastolic BP. This increase in BP was more marked in rural areas and elderly subjects. Prevalence of hypertension was significantly higher during winter (23.72%) than in summer (10.12%). Conclusion BP increases significantly during winter season as compared to summer season. Increase is more marked in rural areas and elderly subjects. Seasonal variation in BP should be taken into account while looking at prevalence of hypertension in epidemiological studies.
ABSTRACT
Background: There is need to evaluate influence of weather changes on blood pressure in human population that has often been ignored in clinical practice guidelines. Objectives: Present study was planned to find the seasonal variation of blood pressure. Methods: Seasonal variation in blood pressure was examined in 1081 participants of age 18 years and over from both genders, 540 from rural and 541 from urban practice area of Department of Community Medicine of tertiary care teaching hospital of Ludhiana. Information was obtained on demographic and socioeconomic characteristics and socio-economic status followed by clinical examination. Anthropometric measurements included weight, height, waist circumference, hip circumference, waist and hip ratio, Body Mass Index. Blood pressure was recorded and classified based on JNC VII criteria. Data was obtained on four different seasons (winter, summer, monsoon and post-monsoon) as defined by Indian meteorological department. Results: Present study showed that there is significant increase in the blood pressure in study population during winter and significant fall in summer in both systolic (SBP) and diastolic blood pressures (DBP) irrespective of age, sex, socioeconomic status, occupation. The variation in SBP between summer and winter season was maintained across all the age groups except in elderly where maximal difference was observed in monsoon - summer seasons. Mean SBP and DBP were higher in 41 to 50 years and more than 60 year age group; females have a higher increase in both mean SBP and DBP. Advancement in age and females gender confirmed more significant changes in blood pressure across ambient temperatures. Conclusion: Our study showed that climatic changes influence the blood pressure recordings and should also be considered for management of hypertension.