ELSA – Brasil

NOMBRE

Estudo Longitudinal da Saúde do Adulto (ELSA-Brasil) / The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

PRINCIPAL INVESTIGATORS

Steering Committee: Paulo A. Lotufo/Isabela M. Bensenor; Sandhi M.Barreto/Luana Giatti; M.Ines Schidmt/Bruce B. Duncan; Sheila Alvim/M.Conceição Almeida; Rosane Griep/M.Jesus Fonseca, JG Mill /M.Carmen Molina.

INTRODUCTION

Background to establish the cohort: Most of our knowledge about chronic disease epidemiology comes from large cohort studies conducted in the United States and Western Europe. Very few such studies have been done in low- and middle-income countries, where the prevalence rates of effect modifiers may differ from those in high-income countries, and novel risk factors may be present.

Aims: The primary study objectives of ELSA-Brasil are to investigate the incidence and progression of cardiovascular diseases and diabetes and their biologic, behavioral, environmental, occupational, psychological, and social factors.

Timeline: Organization: 2004-08; Baseline: 2008-10; Second visit: 2012-14; Third visit: 2017-18.

METHODS

Population and Sampling: 15,105 men and women civil servants living in six Brazilian cities (São Paulo, Belo Horizonte, Porto Alegre, Salvador, Rio de Janeiro, and Vitoria).

Enrolment: All active or retired employees of the six institutions aged 35–74 years were eligible for the study. Our sample includes volunteers (76% of the final sample) and actively recruited participants (24%), the latter being recruited from listings of civil servants. Exclusion criteria were current or recent (<4 months before the first interview) pregnancy, intention to quit working at the institution shortly, severe cognitive or communication impairment, and, if retired, residence outside of a study center’s corresponding metropolitan area.

Exposures and health events: height (standing/sitting), weight with body impedance; circumferences (neck/waist/hip); blood pressure (arm and brachial); retinoscopy; hepatic sonogram; echocardiogram; hand-grip strength; ECG at resting and heart rate variability; pulse wave velocity; IMT carotid a. and femoral a.; exercise testing; OGTT for diabetes diagnosis. Exposures (subsetting): coronary artery calcium score and CT coronary angiogram; sleep evaluation; hepatic/VAT CT; spinal and femur densitometry; religiosity and spirituality. Instruments: Questionnaire applied by trained nurses: diet (FFQ), migration history, reproductive health, cognition tests, psychiatric evaluation; job-stress at work; perception of home environmental; alcohol intake; comorbidities.

Outcomes: Incidence of hypertension/diabetes/high cholesterol/renal function decline between visits; fatal and non-fatal cardiovascular events; all causes of hospitalization; and causes of deaths.

Biological samples: 6 samples of fasting serum and fasting plasma, and two samples of serum and plasma after OGTT stored in liquid nitrogen tanks under -170ºC at a central biobank Follow-up: Cold and hot-pursuit for clinical events by one phone call per year.

RESULTS

Population features: In general, these goals were achieved, though with slightly more women and younger persons and slightly fewer unskilled workers. As measured by self-rated race/color, 52% of participants are white, 28% are pardos (‘‘browns’’ or of mixed color), 16% are black, 3% are Asian (mainly Japanese Brazilians), and 1% are indigenous.

Follow-up: From all participants of baseline, 4% declined to perform the second visit. However, the compliance for the phone call interview yearly is 99%.

Main results: So far, ELSA-Brasil published 200 papers (free copies shared under request) related to baseline data related to cardiovascular risk factors, psychiatric characteristics of the sample.

DISCUSSION

External validation: a comparison of ELSA-Brasil risk factors with the National Surveillance Survey shows values very similar as Low leisure-time physical activity 76.9 75.2; Current smoking 13.1 15.7; Former smoking 30.0 30.1; previous diagnosis of hypertension 34.1 35.3; previous diagnosis of diabetes 8.8 9.6 and Overweight (25_ BMI< 30 kg/m2) 40.2c 46.9.

Data sharing: Sharing individual-level data with international collaborators requires specific approval from the local IRB. This procedure is usually on a case-by-case basis (project and collaborator-wise) and poses a significant burden regarding processing time. It is the way to go for specific types of data-sharing when there is a particular hypothesis being tested.

FUNDING SOURCES

Ministry of Health and state agencies as FAPESP (Sao Paulo).