The Barbados Health of the Nation Survey

Investigators:

Christina Howitt, Ian Hambleton, Angela Rose, Nigel Unwin

Other investigators:

Kenneth George, Ministry of Health of the Government of Barbados, and Alafia Samuels, Faculty of Medical Sciences, Cave Hill Campus

Funding Obtained:

640,000 BDS (320,000 USD) from the Ministry of Health Barbados

Start Date:

October 2011

End Date:

December 2013

Rationale:

This study was designed to assess in the adult population of Barbados the prevalence of diabetes, hypertension and associated social, behavioural and biological risk factors. It provides a basis for guiding and monitoring preventive and treatment interventions. Nested within this study were three studies on sub‐sections of the total sample addressing specific aspects of non‐communicable disease risk. An additional study made use of the whole Health of the Nation sample to enquire about health care usage and estimate health care costs. These studies are described separately below.

Methods:

Sampling and recruitment was undertaken in collaboration with the Barbados Statistical Service. Multistage probability sampling was used to select a representative sample of the adult population (> 25 years). Participants were interviewed using standard questionnaires, underwent anthropometric and blood pressure measurements, and provided fasting blood for glucose, glycated haemoglobin, and a lipid profile. Plasma and cells have been stored for future analyses. Data are weighted for sampling and non‐response, and age‐ and sex‐standardised to the 2010 Barbados population. At the time of writing the main report for the Ministry of Health has been completed, and the first main paper submitted for publication, with further papers in preparation. In the results presented here log binomial regression models were used to calculate prevalence ratios.

Main Results:

Study participation rate was 55.0%, with 764 women, 470 men. Prevalence of obesity was 33.8% (95% CI: 30.7, 37.1); hypertension 40.6% (95% CI: 36.5, 44.9); and diabetes 18.7% (95% CI: 16.2, 21.4). Compared with women, men were less likely to be obese (prevalence ratio 0.5; 95%CI 0.4–0.7), or physically inactive (0.5; 0.4–0.6), but more likely to smoke tobacco (4.1; 2.5–6.7) and consume large amounts of alcohol in a single episode (4.6; 2.7–7.6). ). Both diabetes (0.83; 0.65‐1.05) and hypertension (0.89; 0.79‐1.02) were lower in men, but not significantly so. In women, higher educational level was significantly related to higher fruit and vegetable intake, more physical activity, less diabetes and less hypercholesterolaemia (p values: 0.01–0.04). In men, higher education was significantly related only to less smoking (p<0.05). Differences by occupational category were limited to smoking in men and hypercholesterolaemia in women.

Expected impact:

This study, funded by the Ministry of Health of Barbados, is providing data on the burden and control of hypertension, diabetes and their risk factors. It is central the Ministry’s surveillance of NCDs. In addition, the study is providing new knowledge of international relevance, including on the social distribution of these conditions.

Next Steps / Future Plans:

The Ministry intends that Health of the Nation surveys will be conducted every 4 years, with the next being planned for 2016/17. The lessons learned from the sampling and recruitment in this current study should lead to an improved response rate, and for a sample size of around 2000 for the next study. It is our intention to turn these sequential cross sectional studies into cohort studies, with follow up through the Barbados National Registry for incident myocardial infarction, stroke and cancer, plus mortality follow up through the death registration system. Establishing consecutive cohorts in this way will, over 5 to 10 years, enable the exploration of risk factors in this population for common NCDs and the derivation of locally appropriate risk scores for clinical decision making. There will also opportunities for making use of the stored plasma (stored at minus 80 degrees C), including on the predictive value of specific biomarkers.

Publications:

The first main paper from this study is currently with BMJ open and describes the distribution of risk factors by markers of socio‐economic status. Papers currently in preparation include a description of the coverage and control of hypertension; the agreement between fasting glucose and HBA1c in defining hyperglycaemia in this population; and the derivation of local appropriate cut points for generalised and abdominal obesity. There were three presentations from this study at the European Diabetes Epidemiology Group meeting in April 2015 and one at the CARPHA research meeting June 2015. There were three presentations of core study findings at the Barbados Association of Medical Practitioners meeting in May 2015.

Training opportunities:

Data from the Health of the Nation is being used by two Doctorate in Public Health candidates for their research theses, and by two Masters’ students for their theses. One doctor is current accessing participants with previously diagnosed diabetes from the dataset to undertake research towards his Medical Doctorate. Two of the sub‐studies (described below) are being used by two PhD candidates.