The Barbados Health of the Nation Survey – Physical Activity Sub‐Study

Investigators:

Christina Howitt, Ian Hambleton, Nigel Unwin

Other investigators:

Soren Brage and Kate Westgate, Physical Activity Group, MRC Epidemiology Unit, University of Cambridge, UK

Funding Obtained:

Included within the total for the main study

Start Date:

October 2011

End Date:

December 2013

Rationale:

The Barbados Physical Activity Study aimed to estimate physical inactivity in young and middle‐aged Barbadian adults, and to provide information on physical activity patterns, in order to inform the development and evaluation of future interventions. This study was made possible by collaboration with the MRC Epidemiology Unit at the University of Cambridge, who have the expertise and hardware for the objective assessment of physical activity.

Methods:

Participants of the Health of the Nation Study aged 25 to 54 years were randomly selected, with the initially aim of a total sample size of 500. Each participant was asked to wear a combined movement and heart rate monitor (Actiheart) for seven days (objective physical activity measurement), and complete the Recent Physical Activity Questionnaire (RPAQ) (subjective measurement). The RPAQ also provided information on where people accumulate their activity and the types of activities carried out.

Main Results:

Objective data were collected for 354 individuals. Analysis and write up is in progress. At the time of writing the following results are worthy of note:

• Most adults do not meet the recommended 150 minutes of moderate‐to‐vigorous activity per week, and people tend to report more activity than they actually do. The prevalence of objectively assessed inactivity was 75.2% (68.7, 80.8), compared with 46.9% (39.4, 54.5) for subjectively assessed inactivity.
• There was a significant difference in the prevalence of objective inactivity in the overweight/obese vs. normal BMI categories (80.3% vs. 65.9%; p value=0.03). A significant difference in mean objective physical activity energy expenditure was also observed in overweight/obese vs. normal BMI categories: (41.5 vs. 49.0 kJ/kg/day; p value=0.005). These differences were not found when subjective assessments were used.
• Few people report using active forms of transportation, even occasionally. Only 13.5% (10.6, 17.1) report ever walking to work (includes those who always, usually, or occasionally walk), and there were no reports of cycling.
• People report spending on average 3 hours each day watching television, and between 1 and 2 hours each day on the computer in their spare time.
• Men report spending more time in and participating in a greater variety of leisure activities than women. Walking and gardening were the most popular activities for both sexes. Further analyses will address the following:
• Validation of the RPAQ against the objective data.
• Investigation of the impact of different physical activity behaviours on metabolic risk.
• Quantification of the contribution of physical inactivity to hypertension and hyperglycaemia.

Expected impact:

This study provides the first objective assessment of physical activity in adults in the Caribbean. It is providing new knowledge in this setting on the validity of subjective approaches to the assessment of physical activity and on the contribution of physical inactivity to the burden of NCDs.

Next Steps / Future Plans:

Further analyses, as described above. The findings will be used to inform the surveillance of physical activity, and to help plan interventions to reduce physical inactivity.

Publications:

Major publications that are planned include: physical activity patterns within Barbadian adult population, and the predictors of different types of activity (e.g. leisure time, work related, and sedentary time); validation of the RPAQ questionnaire against the Acti‐Heart data; estimates of the attributable risks from physical inactivity for diabetes, hypertension and cardiovascular disease in this population; comparison of self‐rated physical activity levels (i.e. how active people consider themselves to be) with objectively assessed activity.

Training opportunities:

This study is the basis of Christina Howitts PhD, and her supervisory team includes Dr Soren Brage from the MRC Epidemiology Unit, University of Cambridge, UK.