The discovery of insulin in 1921 changed the prognosis for people with type 1 diabetes. A century later, availability and affordability of insulin remain a challenge in many parts of the globe. Using the WHO’s framework on understanding the life cycle of medicines, this review details the global and national challenges that affect patients’ abilities to access and afford insulin. Current research and development in diabetes has seen some innovations, but none of these have truly been game-changing. Currently, three multinational companies control over 95% of global insulin supply. The inclusion of insulin on the WHO’s Prequalification Programme is an opportunity to facilitate entry of new companies into the market. Many governments lack policies on the selection, procurement, supply, pricing and reimbursement of insulin. Moreover, mark-ups in the supply chain also affect the final price to the consumer. Whilst expenses related to diabetes are mostly covered by insurance in high-income countries, many patients from low- and middle-income countries have to pay out of their own pockets. The organisation of diabetes management within the healthcare system also affects patient access to insulin. The challenges affecting access to insulin are complex and require a wide range of solutions. Given that 2021 marks the centenary of the discovery of insulin, there is need for global advocacy to ensure that the benefits of insulin and innovations in diabetes care reach all individuals living with diabetes. Graphical abstract

Travel has individual, societal and planetary health implications. We explored socioeconomic and gendered differences in travel behaviour in Africa, to develop an understanding of travel-related inequity. We conducted a mixed-methods systematic review (PROSPERO CRD42019124802). In 2019, we searched MEDLINE, TRID, SCOPUS, Web of Science, LILACS, SciELO, Global Health, Africa Index Medicus, CINAHL and MediCarib for studies examining travel behaviour by socioeconomic status and gender in Africa. We appraised study quality using Critical Appraisal Skills Programme checklists. We synthesised qualitative data using meta-ethnography, followed by a narrative synthesis of quantitative data, and integrated qualitative and quantitative strands using pattern matching principles. We retrieved 103 studies (20 qualitative, 24 mixed-methods, 59 quantitative). From the meta-ethnography, we observed that travel is: intertwined with social mobility; necessary to access resources; associated with cost and safety barriers; typified by long distances and slow modes; and dictated by gendered social expectations. We also observed that: motorised transport is needed in cities; walking is an unsafe, ‘captive’ mode; and urban and transport planning are uncoordinated. From these observations, we derived hypothesised patterns that were tested using the quantitative data, and found support for these overall. In lower socioeconomic individuals, travel inequity entailed reliance on walking and paratransit (informal public transport), being unable to afford travel, travelling less overall, and travelling long distances in hazardous conditions. In women and girls, travel inequity entailed reliance on walking and lack of access to private vehicles, risk of personal violence, societally-imposed travel constraints, and household duties shaping travel. Limitations included lack of analytical rigour in qualitative studies and a preponderance of cross-sectional quantitative studies (offering a static view of an evolving process). Overall, we found that travel inequity in Africa perpetuates socioeconomic and gendered disadvantage. Proposed solutions focus on improving the safety, efficiency and affordability of public transport and walking.

Background: An inverse association between vitamin D status and cardiometabolic risk has been reported but this relationship may have been affected by residual confounding from adiposity and physical activity due to imprecise measures of these variables. We aimed to investigate the relationship between serum 25-hydroxyvitamin D (25(OH)D) and cardiometabolic risk factors, with adjustment for objectively-measured physical activity and adiposity. Methods: This was a population-based cross-sectional study in 586 adults in Cameroon (63.5% women). We assessed markers of glucose homoeostasis (fasting blood glucose (BG), 2 h post glucose load BG, HOMA-IR)) and computed a metabolic syndrome score by summing the sex‐specific z‐scores of five risk components measuring central adiposity, blood pressure, glucose, HDL cholesterol and triglycerides. Results: Mean±SD age was 38.3 ± 8.6 years, and serum 25(OH)D was 51.7 ± 12.5 nmol/L. Mean 25(OH)D was higher in rural (53.4 ± 12.8 nmol/L) than urban residents (50.2 ± 12.1 nmol/L), p = 0.002. The prevalence of vitamin D insufficiency (<50 nmol/L) was 45.7%. There was an inverse association between 25(OH)D and the metabolic syndrome score in unadjusted analyses (β = −0.30, 95% CI −0.55 to −0.05), which became non-significant after adjusting for age, sex, smoking status, alcohol intake and education level. Serum 25(OH)D was inversely associated with fasting BG (−0.21, −0.34 to −0.08)), which remained significant after adjustment for age, sex, education, smoking, alcohol intake, the season of data collection, BMI and physical activity (−0.17, −0.29 to −0.06). There was an inverse association of 25(OH)D with 2-h BG (−0.20, −0.34 to −0.05) and HOMA-IR (−0.12, −0.19 to −0.04) in unadjusted analysis, but these associations became non-significant after adjustment for potential confounders. Conclusion: Vitamin D insufficiency was common in this population. This study showed an inverse association between vitamin D status and fasting glucose that was independent of potential confounders, including objectively measured physical activity and adiposity, suggesting a possible mechanism through insulin secretion.

We aimed to determine and compare HRV parameters in poorly and well controlled type 2 diabetes. 54 normotensive type 2 diabetes patients without clinical signs of CAN were enrolled; 29 poorly controlled (HbA1c ≥ 7%) and 25 controls matched for age, sex and BMI. HRV analysis was performed using 24-h ambulatory ECG, with automatic estimation of the time and frequency domain ranges. Comparisons were performed using Mann–Whitney test. We included 54 participants (26 males) aged 56 years [43–62], with known duration of diabetes 3 years [1–7]. HbA1c was 10.1% [9.1–11.9] vs 5.3% [5.1–6.3] (p < 0.001). Blood pressure was 126 mmHg [121–130] vs 124 mmHg [113–133] in the poorly controlled group and the well-controlled group respectively (p = 0.5). 24-h mean heart rate was significantly higher in poorly controlled vs well controlled patients (79 bpm [77–83] vs 75 bpm [69–79], p = 0.006). In the time domain analysis, markers of the overall variability were lower and thus altered in the poorly controlled group (SDNN: 102 ms [90.5–111.1] vs 112.3 ms [104.4–131.2], p = 0.01 and SDANN 88 ms [72.9–99.7] vs 97.8 ms [91.8–114.5], p = 0.01). The frequency domain analysis showed trends towards lower values of sympathovagal balance markers in the poorly controlled group. Reduced HRV is associated with poorly controlled type 2 diabetes mellitus and may be an early marker in clinical practice.

Purpose: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key regulator of circulating LDL cholesterol. There are inconsistent data in some populations concerning the association between PCSK9, LDL and CRP. The emerging importance of the inhibition of PCSK9 for the treatment of hypercholesterolemia warrants investigations in different populations. The aim of this study from a Sub-Saharan African population was to evaluate the association between PCSK9 and hs-CRP levels and plasma lipid levels in patients with type 2 diabetes (T2D) and obese and lean controls. Patients and methods: A cross-sectional analytical study was conducted in a major hospital in Yaoundé, Cameroon in a cohort of 162 participants (53% females). There were 54 non-obese T2D patients matched for age and sex to 54 obese nondiabetic and 54 nondiabetic lean subjects. PCSK9 level was assessed by sandwich ELISA method and hsCRP by nephelometry. Results: PCSK9 and hs-CRP levels were significantly higher in obese and T2D subjects when compared to lean controls (pr=0.56, p=0.02 and r=0.2 and p=0.1, respectively). Multilinear regression analysis identified BMI as an independent predictor for PCSK9 levels and this association was maintained after adjustment for confounders; adjusted β-coefficient; 36.1 (95% CI; 29.2–47.4). We did not find an association between PCSK9 and any plasma lipid levels in obese and T2D subjects, nor between PCSK9 and hs-CRP levels. Conclusion: Obese and type 2 diabetes subjects have higher PCSK9 levels when compared to lean controls, suggesting that these metabolic states potentially impact PCSK9 levels in Cameroonian patients.