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Open Access Research article

Rural to urban migration and changes in cardiovascular risk factors in Tanzania: a prospective cohort study

Nigel Unwin1*, Peter James1, Dorothy McLarty1, Harun Machybia2, Peter Nkulila3, Bushiri Tamin4, Mkay Nguluma3 and Richard McNally1

Author Affiliations

1 Institute of Health and Society, Newcastle University, Newcastle, NE2 4AX, UK

2 Regional Medical Officer, PO Box 259, Mbeya, Tanzania

3 Morogoro Regional Hospital, PO Box 110, Morogoro, Tanzania

4 Muhimbili University of Health and Allied Sciences, PO Box 65001, Dar es Salaam, Tanzania

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BMC Public Health 2010, 10:272  doi:10.1186/1471-2458-10-272

Published: 24 May 2010

Abstract

Background

High levels of rural to urban migration are a feature of most African countries. Our aim was to investigate changes, and their determinants, in cardiovascular risk factors on rural to urban migration in Tanzania.

Methods

Men and women (15 to 59 years) intending to migrate from Morogoro rural region to Dar es Salaam for at least 6 months were identified. Measurements were made at least one week but no more than one month prior to migration, and 1 to 3 monthly after migration. Outcome measures included body mass index, blood pressure, fasting lipids, and self reported physical activity and diet.

Results

One hundred and three men, 106 women, mean age 29 years, were recruited and 132 (63.2%) followed to 12 months. All the figures presented here refer to the difference between baseline and 12 months in these 132 individuals. Vigorous physical activity declined (79.4% to 26.5% in men, 37.8% to 15.6% in women, p < 0.001), and weight increased (2.30 kg men, 2.35 kg women, p < 0.001). Intake of red meat increased, but so did the intake of fresh fruit and vegetables. HDL cholesterol increased in men and women (0.24, 0.25 mmoll-1 respectively, p < 0.001); and in men, not women, total cholesterol increased (0.42 mmoll-1, p = 0.01), and triglycerides fell (0.31 mmoll-1, p = 0.034). Blood pressure appeared to fall in both men and women. For example, in men systolic blood pressure fell by 5.4 mmHg, p = 0.007, and in women by 8.6 mmHg, p = 0.001.

Conclusion

The lower level of physical activity and increasing weight will increase the risk of diabetes and cardiovascular disease. However, changes in diet were mixed, and may have contributed to mixed changes in lipid profiles and a lack of rise in blood pressure. A better understanding of the changes occurring on rural to urban migration is needed to guide preventive measures.