Abstract P028: Length of Residence in Urban Environment based on MODIS Satellite Derived Urban Land Cover is an Independent Predictor of Blood Pressure
Background: Prevalence of hypertension (HTN) in urban populations in Southeast Asia is increasing. We assessed the association between time residing in urban area (using MODIS satellite based land cover (LC) at two different time points) and blood pressure (BP) of residents in Chennai, a rapidly expanding metropolitan city in India, and surrounding non-urban areas.
Methods: In the cross-sectional analysis, 8080 participants (mean age 42 years; 58% female) spread over a 65 x 80 km area constituted the study sample. BP measures included brachial systolic (SBP) and diastolic (DBP), and central systolic (cSBP) by applanation tonometry. Residences were geolocated in ArcGIS and joined with LC data for the years 2000 and 2010 to classify residences into urban before 2000 (n=1851), urban after 2000 (n=1444) and nonurban (n=4766) [figure]. Generalized linear and logistic regression models assessed the effect of length of residence in urban areas on BP and odds for HTN (SBP ≥140; or DBP ≥90 or reported history), respectively. All models were adjusted for age, gender, BMI, physical activity, LDL, blood sugar, smoking, stress, and anxiety status Results: Residents in urban areas before 2000 had significantly (p<0.01) higher brachial BP (SBP=130.6; DBP=79.6) and cSBP (117.2) and higher prevalence of HTN (37%) than those in urban areas after 2000 (SBP=121.6; DBP=76.9; cSBP=114.3; HTN= 27%) and non-urban (SBP=118.4; DBP=74.9; cSBP=114.1; HTN= 22%). In adjusted linear regression models length of residency in the urban areas was independently associated with BP (SBP (β=0.24); DBP (β= 0.13); cSBP (β=0.096); p<0.01). After multivariable adjustments, compared to living in nonurban LC, residents in urban areas before 2000 had significantly higher odds for HTN [OR = 2.05 (1.79, 2.35)] than those residing after 2000 [OR = 1.13 (0.97, 1.32)].
Conclusions: Residential length of time in an urban area was an independent predictor of BP and of HTN. Future research is needed to determine what components of the urban environment contribute to increased BP.
Author Disclosures: K.J. Lane: None. J. Sunderarajan: None. V. Harivanzan: None. K.K. Chui: None. S. Thanikachalam: None. M. Thanikachalam: None.
- © 2015 by American Heart Association, Inc.