Worldwide trends in blood pressure and diabetes

Abstract

High blood pressure and diabetes are leading causes of loss of health and included in the targets set by the World Health Organization to control non-communicable diseases (NCDs) globally. My thesis aims to provide comparable estimates of levels and trends in blood pressure and diabetes worldwide. Data were collated via the NCD Risk Factor Collaboration (NCD-RisC) network, from population-based studies that had measured blood pressure from 1975 to 2015, or had measured one or more biomarkers of diabetes from 1980 to 2014. A total of 1,479 studies with 19.1 million participants aged 18 years or older were used in the blood pressure analysis, and 751 studies with 4.4 million participants in the diabetes analysis. I used a Bayesian hierarchical model to estimate trends for 200 countries in the world. Overall, there have been divergent trends in blood pressure, seeing a shift of high blood pressure levels from high-income countries to low- and middle-income countries. The global number of adults affected with raised blood pressure has almost doubled since 1975, driven by population growth and ageing, reaching 1.13 billion in 2015. Similarly, age-standardised diabetes prevalence has increased in almost every country, except those in north-western Europe where the trends have been largely flat. The number of adults affected with diabetes has nearly quadrupled, totalling 422 million in 2014. If post-2000 trends continue, for the world as a whole, the probabilities of meeting the global targets of 25% reduction in raised blood pressure and no rise in diabetes compared to their 2010 levels are 0% for blood pressure and ≤1% for diabetes. A preliminary analysis showed diminishing associations of blood pressure and diabetes with national macroeconomic indicators over time, and weak associations with some measures of food and nutrition.