PRECISION PUBLIC HEALTH: Shifting the focus from group averages to individual variations to better understand the distribution of Body Mass Index over time and across social and geographical contexts.

Research problem and specific questionsObesity is a major public health concern globally, also affecting Sweden.

Improved analytical tools for the identification of high-risk groups in vulnerable settings will better inform decision-makers in their design and implementation of intervention strategies to reduce obesity.

Therefore, to address the knowledge gap in mean-centric traditional risk factor epidemiology, this project will include variance and individual heterogeneity with average estimates to provide deeper insights into the varying individual, social, and contextual patterning of BMI in Sweden.

Thus, our main aims are:1) To analyse the change in BMI distribution over time and across and within social and demographic groups.2) To examine variation in BMI among multiple demographic and socioeconomic groups simultaneously.3) To map geographical variation in BMI over time to help generate evidence-informed and tailor-made targeted actions and policies at a local level (i.e., neighbourhoods).Data and methodBoth register and survey data will be utilized in this project: (i) national data on early pregnancy BMI from 1992-2017 extracted from the Medical Birth Register (1,470,050 records), and (ii) regional (Västerbotten) survey data for both men and women at early pregnancy from 2011-2020 (41,918 records).

Both datasets are enriched with linked social data from Statistics Sweden and available at the Umeå SIMSAM Lab.Plan for project realisationThe project will use existing infrastructure and equipment at the Department of Epidemiology and Global Health as well as the Umeå SIMSAM Lab, both at Umeå University.

The main cost is salaries for the interdisciplinary research team.

Additionally, the availability of both national and regional data combined with research group capacity and experience in utilizing such data will ensure that the project will be implemented successfully.RelevanceOverall, the project will help encourage greater precision in evidence used to inform public health policies.

Distinct patterning in the magnitude of variation between individuals within a defined population will have important implications for how we assess and interpret the health of populations over time and inform policy for universal versus targeted strategies aimed at improving health.

Policies and actions locally and nationally aimed at reducing BMI and related social and contextual inequalities will benefit by targeting the right population at the right place.