Trends in all-cause and cause-specific mortality by BMI levels in England, 2004–2019: a population-based primary care records study

Background: In the UK, obesity rates are rising concurrently with declining mortality rates. Yet, there is limited research on the shifts of mortality trends and the impact of obesity-related mortality. In this study, we examine mortality trends and the cause-specific proportional composition of deaths by body mass index. Methods: We used primary healthcare records from the Clinical Practice Research Datalink between 2004 and 2019, linked to national death registration data. There were 880,683 individuals with at least one BMI measurement and a 5-year survival period. We used discrete Poisson regression and joinpoint analysis to estimate the all-cause and cause-specific mortality rate and significance of the trends. Findings: Between January 1, 2004, and December 31, 2019, all-cause mortality rates declined in the obese category by 3% on average per year (from 23.3 to 14.6 deaths per 1000 person years) in males and 2% on average per year (from 12.5 to 9.4 deaths per 1000 person years) in females. Cardiovascular disease mortality declined 7% on average per year (from 12.4 to 4.4 deaths per 1000 person years) in males and 4% on average per year (from 5.5 to 3.0 deaths per 1000 person years) in females in the obese category. Increases in mortality rates from neurological conditions occurred in all BMI categories in males and females. By the end of the study, cancers became the primary contributor of death in males in all BMI categories and females in the overweight category. Interpretation: There have been significant declines in all-cause and cardiovascular disease mortality in males and females, leading to a diversification of mortality, with cancers contributing to the highest proportion of deaths and increases in causes such as neurological and respiratory conditions. Further screening, prevention, and treatment implementation for a broader set of diseases is necessary for continued mortality improvements.</p

Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight

From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions