Mauritius is located in the southern Indian Ocean with a population of 1.3 million in 2023. Mauritius is a multiethnic nation with 68% South Asian, 27% African (Creole), 3% Chinese and 2% Franco Mauritians. Seven population-based cross-sectional surveys using standardised protocols were conducted between 1987 and 2021). The participation rate has been over 85% in each survey. At each survey, participants were interviewed about living conditions, lifestyle and health, and anthropometry and blood pressure were measured. Biochemistry including lipids and an oral glucose tolerance test (OGTT) were performed Electrocardiograms (ECG) were recorded in participants aged 35 years and older. Previous participants were followed up in 2007 and 92% were successfully traced. Studies with identical methodology have been performed on the neighbouring island Rodrigues where the majority of the population are Creoles.
Mauritius and Rodrigues are islands in the south-eastern part of the Indian Ocean. Major changes in lifestyle have been seen during the last fifty years, including less physical activity and introduction of a westernised diet. In parallel, the disease panorama has changed from high infant mortality and infectious diseases to lifestyle-related diseases such as cardiovascular disease and type 2 diabetes. The population in Mauritius are descendants to immigrants from South Asia, Africa and China, i.e., approximately 60% of the world population are represented. Mauritius is probably the only developing country that has followed the development of non-communicable diseases (NCD) and associated risk factors over a long time-period and continues to do so. In the mid-eighties, the Mauritian government initiated a study on the prevalence of type 2 diabetes and cardiovascular disease, in collaboration with WHO and international experts. Altogether seven population-based surveys have been performed between 1987 and 2021, and approximately 39 000 (!) examinations have been recorded. The intention is to repeat the survey every fifth year. The ethnicities of the participants have been 71% South Asians (India/Pakistan), 24% Creoles (Africa) and 5% Chinese, which reflects well the ethnical distribution of the population. Previous participants were followed up in 2007 and 92% were successfully traced. Studies have also been performed on the neighbouring island Rodrigues where the majority of the population are Creoles. During the follow-up survey in 2010, 97% of the 9 700 participants were traced. At each survey, information was given and an individual consent form was signed. See attached the local (in Mauritius) ethical approval and consent form from the Mauritius survey 2021. At each survey, participants were interviewed about living conditions, lifestyle and health, and anthropometry and blood pressure were measured. Biochemistry including lipids and an oral glucose tolerance test (OGTT) were performed Altogether approximately 28 000 electrocardiograms (ECG) were recorded in participants aged 35 years and older, all of which have been coded in Kaunas, Lithuania for signs of ischemic heart disease (Minnesota criteria) and myocardial hypertrophy. The Mauritius NCD study was initially administrated by the International Diabetes Institute in Melbourne, Australia under the leadership of Professor Paul Zimmet together with Professor Jaakko Tuomilehto (Finland) and Professor George Alberti (United Kingdom). Today, the study is administrated and financed by the Ministry of health in Mauritius under the leadership of Doctor Sudhir Kowlessur. Professor Stefan Söderberg at the Department of Public Health and Clinical Medicine, Umeå University, Sweden was introduced to the Mauritius NCD study during his postdoc (2001-2002) in Professor Zimmet's research team at IDI in Melbourne. Söderberg has since then continued to assist in the performance of the surveys and to analyse data. Today, Umeå university and the Department of Public Health and Clinical medicine have been granted the privilege to curate and analyse data generated in the Mauritius and Rodrigues NCD study. Each survey has been evaluated and approved by the local ethics committee in Mauritius (see attached the approval from 2021). Analysing data in Sweden has been approved by the Swedish Ethical Authority (2023-07199-01).
Study Type
OBSERVATIONAL
Enrollment
39,082
Unnamed facility
Port Louis, Mauritius
Mortality
According to household interviews, death certificates from central registers at Ministry of Health and Wellness. 1. Household interviews: "Is the participant alive? If dead, do you have a copy of the death certificate? When did the participant die?" 2. Central registers: Vital status, if dead, date and cause of death from death certificates" Combining 1 and 2 will give date and cause of death. Absolute numbers and mortality rates will be reported for all and in subgroups i.e. sex, age-strata, ethnicity.
Time frame: Up to 20 years from the baseline survey
Diabetes Mellitus
Determined according to WHO criteria. i.e. data from oral glucose tolerance tests and questionnaires (glucose-lowering medication). 1. A 75-g oral glucose-tolerance test is used on all non-pregnant participants, except those taking insulin or oral hypoglycaemic drugs, was performed after an overnight fast, and plasma glucose (mmol/L) are measured before the test and after two hours. 2. The questionnaire includes the question: "Do you take glucose-lowering medication, insulin or tablets, yes/no". The participant has diabetes if fasting glucose ≥ 7.0 mmol/ and/or two-hour glucose ≥ 11.1 mmol/L and/or answer yes to taking glucose lowering medication, and prediabetes if fasting glucose ≥ 6.1 and \< 7.0 mmol/L and/or two-hour glucose ≥ 7.8 and \< 11.1 mmol/L. Numbers and age-standardised incidence and prevalence of prediabetes and diabetes will be reported for all and in subgroups.
Time frame: Up to 20 years from the baseline survey
Cardiovascular disease (CVD)
Determined by analysis of serial ECG recordings, data from official registers and questionnaires. ECGs and signs of coronary heart disease (CHD) according to the Minnesota Code (MC) classification. Probable CHD (MC: 1-1 to 1-2 (large Q and QS)) and possible (CHD) (MC: 1-3 (small Q and QS), 4-1 to 4-4 (ST depression), 5-1 to 5-3 (T wave inversion and flat) and 7-1 (left bundle branch block)). Probable CHD will be interpreted as previous myocardial infarction (MI). From central registers: Date and related ICD 10 codes for hospital admissions. ICD codes I21-23 will be interpreted as MI, and I60-61 and I63-64 as stroke. Survey: Affirmative answer to any of these questions: Do you have angina, myocardial infarction (including by-pass surgery and PCI), and/or stroke" will be labelled as previous CVD. CVD is present if probable CHD and/or ICD codes found for MI or stroke and/or affirmative answer to surve questions.
Time frame: Up to 20 years from the baseline survey
Hypertension
Blood pressure (BP) is measured using an automated BP monitor (Omron Digital Auto Blood Pressure Monitor). The questionnaire includes the question: "Do you take BP lowering medication, yes/no". Hypertension is defined as a systolic BP ≥ 140 mmHg and/or diastolic BP ≥ 90 mmHg, and/or answer "yes" to the use of BP lowering drugs. Numbers and age-standardised incidence and prevalence of hypertension will be reported for all and in subgroups.
Time frame: Up to 20 years from the baseline survey
Obesity
Height (in meter, m) and weight (in kilogram, kg) will be measured in light clothing without shoes. Waist circumference (in centimeter, cm) is measured as the circumference at the mid-point between the iliac crest and the lower margin of the ribs. Hip circumference (in centimeter, cm) is taken as the horizontal measure around the pelvis at the point of maximal protrusion of the buttocks. Waist and hip circumference are measured twice, and the mean will be calculated. Body mass index (BMI) is calculated as weight divided by height squared (kg/m2), and waist to hip ratio (WHR) as waist circumference (cm) divided by hip circumference (cm). Obesity is defined according to BMI as ≥ 30 kg/m2, and central obesity according to waist circumference using ethnic-specific cut-offs. Numbers and age-standardised incidence and prevalence of obesity and central obesity will be reported for all and in subgroups.
Time frame: Up to 20 years from the baseline survey
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