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Origins and intervention in chronic diseases

  • We have specific expertise and well established sites in Malawi to advance the study of diabetes, hypertension and chronic lung disease. The cohesion of this Programme relates to the important emerging epidemic of NCD, driven in Malawi by environmental exposures, urbanisation and increased life-expectancy. The NCD agenda requires urban/rural comparisons, long-term study including birth cohorts and chronic treatment. In resource constrained settings, prevention is essential.
  • In 2015, Nyirenda and Crampin completed the largest population based study of diabetes, hypertension, HIV and cardiometabolic risk factors in SSA. They characterised high rates of hypertension, diabetes, obesity and dyslipidaemias (particularly low HDL-C, which is exacerbated by untreated HIV) in both urban and rural populations. Through the ALPHA network platform, Alison Price (WT Clinical Fellowship) is leading on a multi-site analysis incorporating these data with those from five other sites in SSA of chronic NCD and cardio-metabolic risk factors. 

    Malawi is in a nutritional paradox; 2.8 million of the 17 million population are under-nourished and on food aid. This will get worse as the population is expected to reach 30 million before 2030 and food production cannot keep pace. Yet MEIRU data show that obesity is highly prevalent, particularly in women and even in rural populations, and in individuals of lower socioeconomic status. We have demonstrated that urban women and those at higher socio-economic status are at higher risk of nutritional anaemia, presumably due to a shift from traditional diets.

    Urbanisation is driving much of the increase in cardio-metabolic risk. We are quantifying the effect of urban living on cardio-metabolic traits with large population comparisons and sibling-pair studies of rural-urban migrants.
  • Stroke is common, severe and particularly disabling for Malawians given the lack of rehabilitation specialty care. MEIRU’s ongoing surveillance study in rural and urban Malawi is identifying high rates of stroke and mortality. Recent MLW studies have identified hypertension and HIV as the leading correlates of hospitalised stroke in elderly and younger adults respectively (Benjamin, Neurology and Lancet Neurology). A large multisite study (MEIRU with Uganda and South Africa) will explore the population prevalence of chronic kidney disease secondary to hypertension.
  • Mortimer, Nyirenda and Gordon have recently shown that 38% of Malawians have abnormal spirometry, mainly restrictive (small) lungs (Am J Resp Crit Care Med 2016). Small lungs are associated with chronic lung disease and the high observed prevalence indicates that as the population age, a large burden of disease will emerge. Chronic lung disease is very unlike that in Europe and likely a result of either in utero or early life insults. It is an urgent priority for us to understand the association of symptoms and loss of function with abnormal pulmonary physiology in order to plan (a) preventive strategies and (b) effective therapeutic intervention. MLW also leads the largest intervention study ever to reduce household air pollution - the cluster randomised Cooking and Pneumonia Study (JGHT) to reduce childhood pneumonia. This landmark study will report in late 2016.
  • Nyirenda is expert in diabetes foetal origins and pathogenesis. Building on the unique insights being gained from the MEIRU population studies, a programme of studies on the molecular basis for the development of impaired glucose tolerance and progression to frank disease in SSA will be implemented. A birth-cohort (separate application) combined with existing population data will explore the origins of cardio-metabolic risk in this population from pre-conception influences, through foetal growth secondary to a poor pregnancy environment and early infant development.
    Prevention research will also target early death and loss of vision in the small economically and politically productive section of Malawi’s population. We will conduct trials to determine the efficacy and cost-effectiveness of an improved diabetes care model (protocol-driven use of medication, training in diabetic eye care, incentives and text messages to enhance patient adherence with visits and compliance with medication) as a strategy to reduce the burden of diabetic complications, chiefly diabetic eye disease.
    1. Publication of data from largest carbio-metabolic risk and NCD survey in SSA.
    2. Targeted intervention to improve diabetic control and reduce retinopathy.
    3. Intervention studies to prevent blindness in HIV infected diabetic patients.
    4. Stroke prevention in HIV infected adults by selective anti-hypertensive and anti-inflammatory treatment.
    5. Origins (infectious and environmental) associated with precise phenotypes of chronic lung disease and functional significance of reduced lung volumes determined in cohort studies.
    6. Intervention studies related to environmental risk factors and early life infectious to prevent hypertension and chronic lung disease.
    7. National obesity awareness raised through media and government interaction.