Many populations around the globe are passing through an "epidemiological transition" where disease morbidity and mortality switches from acute infectious to chronic degenerative causes. The population on Saba, in the Netherlands Antilles, has recently gone through such a transition, and hypertension and obesity were said to be extraordinarily high among Saban adults.
In this study, all 4 villages (The Bottom, St. John's, Windwardside, and Hell's Gate) on Saba were evaluated for hypertension and obesity in light of recent and rapid modernization. In addition to a medical and demographic questionnaire, 278 individuals were evaluated for hypertension and obesity through single sitting blood pressure measurements, weight, height, bioelectrical impedence, waist and hip circumferences, and triceps and subscapular skinfolds. Derived measurements included body mass index (BMI), body fat percentage, waist-to-hip ratio, central adiposity, and sum of skinfolds. The results of the study indicate that 40% of the population was hypertensive and 67.7% were overweight or obese according to BMI. Using body fat percentage and waist-to-hip ratio, 52% and 72%, respectively, of adult participants were determined to be overweight or obese.
Phase 2 of the project involved 124 individuals of the 278 who had participated in the original study. This cohort was administered a longer questionnaire designed to determine their relative degree of modernization. The analysis of modernization with the blood pressure and anthropometric data obtained in Phase 1 found that blood pressure v was not positively correlated with any of the measures of modernization, including the Sum of Modernization. Obesity, however, was positively correlated with measures of modernization.
Of the 124 participants, 51 agreed to wear a 24 hour ambulatory blood pressure monitor (Spacelabs, Issaquah, WA) to assess diurnal variation and confirm hypertensive status. Phase 2 confirmed that 40% of the study population was hypertensive. Using 24 hour blood pressure monitoring (awake vs. asleep), diurnal variation was extensive but the lack of nighttime dipping indicates that many people on Saba do not have lower blood pressures while sleeping, which is an indicator of possible disease. In an evolutionary sense, this may also cause an increase in allostatic load and therefore more disease.
Intervention and prevention stategies have been developed and include walking programs and nutrition and exercise classes for adults and children. These programs would be cheap is the resources provided by the medical students and faculty on the island can be used. These strategies will be discussed in person with the Department of Public Health and the community on a trip back to Saba in the summer of 2007. There is significant meed to address these problems on the island, especially the issues of overweight and obesity, which are not very well understood.