Diabetes is on the rise in sub-Saharan Africa, a region that has struggled to produce consistent data on prevalence rates among the general population and in pregnant women, a multidisciplinary group of scientists and health experts observed in a new report. The authors estimate that from 1990 to 2010, the diabetes disease burden in this region increased by nearly 90%.
The report from the Lancet Diabetes & Endocrinology Commission analyzed a decade’s worth of health data representing nearly 40,000 people from a dozen countries, as well as quality data that assessed the effectiveness of more than 6,000 healthcare providers. Findings were published in The Lancet Diabetes & Endocrinology journal.
The report points to lifestyle and economic factors as key contributors to diabetes prevalence in this region, namely the rise in incomes, urbanization, and changing eating and work habits in the sub-Saharan countries. Over the last 35 years or so, the number of individuals older than 20 with body mass indexes exceeding 25 kg/m2 rose from 28 million to 127 million.
Just half of the individuals afflicted with diabetes in sub-Saharan Africa are getting diagnosed, and very few are actually getting treated for it. If unaddressed, the total cost of diabetes in the region could exceed $59 billion by 2030, nearly 2% of the region’s gross domestic product.
Rifat Atun, MBBS, MBA, professor of global health systems at Harvard Chan School and one of the report’s lead authors, fears that this trend could spawn a chronic disease epidemic in this part of the world. “We were alarmed by both the magnitude of the problem, the speed at which diabetes has evolved, and how poorly health systems are responding,” Atun said in a statement.
In the face of this challenge, sub-Saharan Africa’s data on diabetes prevalence figures are sorely lacking elements that could assist in driving improvements. According to the authors, “Most countries do not have data or data collection systems that are sufficiently reliable to enable mounting of a commensurate health-system response.”
The region uses different methodologies to ascertain prevalence, each of which has limitations and yields varying estimates. One popular option among sub-Saharan countries is the World Health Organization’s (WHO) STEPwise surveillance method, which uses fasting glucose to assess burden and has a tendency to overlook early stage cases.
To get firm statistics, the report’s authors relied on NCD Risk Factor Collaboration (NCD-RisC) data. At least in the WHO African region, diabetes prevalence has shown a significant increase, from 3.1% in 1980 to 7.1% in 2014. Even with the NCD-RisC estimates, “the reliability of the prevalence data for individual countries in sub-Saharan Africa is questionable,” the authors observed. Data in at least 21 sub-Saharan countries were either incomplete, outdated, or insufficient.
The region also lacks specifics on gestational diabetes prevalence. A review conducted several years ago found wide variations in prevalence among pregnant women in different countries, ranging from nearly 14% in Nigeria to 0% in Tanzania. Studies and organizations alike have issued differing criteria on diagnosing gestational diabetes. “This variation in criteria makes comparing studies and synthesizing results from studies challenging, both within sub-Saharan Africa and globally,” according to the authors.
Digging deeper into the genetic origins of diabetes, the authors found more substantive information on type 2 diabetes than type 1 for this region. About 80 genetic “risk” loci for diabetes exist worldwide, and a major study was able to replicate 50% of these loci for type 2 diabetes among three sub-Saharan countries. Other genetic studies have pointed to the high risk of type 2 diabetes in Africa. “Studies in sub-Saharan African populations suggest that natural selection has acted on several genomic regions associated with obesity and type 2 diabetes,” the authors observed.
Less is known about the origins of type 1 diabetes genetics in this region. According to the report, “A study of African American populations showed large diversity of HLA DRB1-DQA1-DQB1 haplotypes and genotypes in African, compared with European, descendants.”
The authors seemed skeptical of using genetics as a tool for improving diabetes treatment outcomes or crafting risk prediction scores. In light of growing interest among researchers and funders, they acknowledged that genetics might prove useful in characterizing the disease’s progression in Africa.
To avoid a chronic epidemic in sub-Saharan Africa, the authors recommended pooling international resources to promote new research, training of health workers in diabetes prevention and control, and developing new technologies to screen, diagnose, and treat this disease.
Affordable, point-of-care technologies play an important role in supporting diabetes management. “Low-cost diagnostic devices that enable point-of-care testing of blood glucose, HbA1c, glycosuria, and proteinuria could be used for screening, diagnosis, treatment initiation, and monitoring,” according to the authors.
A number of manufacturers produce these devices, leaving little room for compatibility among instruments. To facilitate the use of these low-cost devices in areas of the world like sub-Saharan Africa and encourage interoperability, the authors suggested that manufacturers develop these tools with interchangeable disposable parts.
“Moreover, international bodies such as WHO have an important part to play in developing the technical standards required for improved integrated diagnostic infrastructures for noncommunicable diseases such as diabetes, just as these bodies did in strengthening diagnostic service infrastructures for infectious diseases such as HIV and tuberculosis,” they stated.