Gender difference in the association between gout at diagnosis and metabolic syndrome in African population: a retrospective cohort study

Introduction

few studies have specifically investigated the link between metabolic syndrome (MetS) and gout in sub-Saharan Africa. This report aimed to evaluate in patients with gout the association between gout at diagnosis and MetS and to assess the gender difference.

Methods

we performed a single-centre retrospective cohort study on all outpatients seen in the Rheumatology Unit of the General Hospital, Douala, Cameroon. We included records of patients with a recent diagnosis of gout according to the American College of Radiology (ACR) criteria. MetS was defined according to the harmonized criteria.

Results

we included 511 patients (415 men), with a mean age at diagnosis of 55.9 ±10.8 years. Women were older than men. The mean serum uric acid was 8.24±2.23 mg/L, with hyperuricemia found in 394 patients (77.1%). MetS was present in 101 patients (19.7% [95% CI: 16.8%-22.1%]), significantly more common in men compared to women (23.6% vs. 10.8%; p<0.001). The main components of the MetS were: increased waist circumference (217 patients, 61.3%), obesity (256 patients, 52.2%), hypertension (208 patients, 40.7%), and diabetes mellitus (52 patients, 10.2%). Furthermore, hypertension, diabetes mellitus, obesity, and increased waist circumference were more frequent in women (p<0.001). There was no difference in dyslipidemia according to gender. The combination of components of the MetS was more frequent in men than women (p<0.001).

Conclusion

MetS are common in newly diagnosed Cameroonian patients with gout, with increased waist circumference, obesity, hypertension and diabetes mellitus being the main components. These components are more common in women, but their combination was more frequent in men.

Epidemiology of Idiopathic Inflammatory Myopathies in Africa: A Contemporary Systematic Review

BACKGROUND

The epidemiology of idiopathic inflammatory myopathies (IIMs) has been extensively studied in America, Europe, and Asia, but remains unclear in Africa.

OBJECTIVE

The aim of this review was to summarize available data on the epidemiology of IIMs in Africa.

METHODS

We searched MEDLINE, EMBASE, and African Journals Online for studies published up to December 30, 2020, and reporting epidemiological data on IIMs in Africa. Data were combined through narrative synthesis. The review protocol was registered with PROSPERO, CRD42020186781.

RESULTS

We included 39 studies reporting 683 cases (71.7% adults) of IIMs. Incidence rates of ~7.5/1,000,000 person-years and 1.2/1,000,000 person-years were estimated for dermatomyositis (DM), whereas polymyositis (PM) had an incidence rate of 8.8/1,000,000 person-years. Prevalence estimates of 11.49/100,000 and 11/100,000 (95% confidence interval, 0-32) were provided for IIMs and the PM subtype, respectively. Mean age at diagnosis ranged from 7.9 to 57.2 years, and 50% to 100% of the patients were females. Main subtypes of adult-onset IIMs were DM (21%-93%) and PM (12%-79%), whereas the commonest juvenile subtype was juvenile DM (5.8%-9%). Skeletal muscle involvement (56%-100%) was the main disease feature, and esophagus was the most commonly affected internal organ (6%-65.2%). Anti-Jo1/histidyl tRNA synthetase (7%-100%) and anti-Mi2 (17%-45%) antibodies were the most frequent myositis specific antibodies. Early mortality was high (7.8%-45%), and main death causes were infections, cancers and organ damage in respiratory and cardiovascular domains.

CONCLUSIONS

Apart from a potential younger age at onset of adult IIMs in Africa, current sparse data mostly suggest a similar epidemiology between Africa and other regions. Further high-quality studies are required to validate these findings.

Epidemiology of Sjögren Syndrome in Africa: A Scoping Review

BACKGROUND

The epidemiology of Sjögren syndrome (SS) has been extensively studied in America, Europe, and Asia.

OBJECTIVE

To summarize available data on the epidemiology of SS in Africa.

METHODS

MEDLINE, EMBASE, and African Journals Online were searched from inception up to May 17, 2020, to identify relevant articles. Data gleaned from these reports have been summarized narratively in this review.

RESULTS

Twenty-one hospital-based studies were included. These studies reported 744 cases of SS. The mean age at diagnosis varied between 28 and 73.6 years, and the female proportion ranged from 83.3% to 100%. There was no population-based incidence or prevalence. Among people with autoimmune and other rheumatic conditions, the frequency of primary SS was in the range 1.9% to 47.6%, whereas that of rheumatoid arthritis-associated secondary SS was in the range 4.3% to 100%. Sicca symptoms were the commonest features, with most frequently involved organs being joints, lungs, and neurological structures. Main autoantibodies were anti-Ro/SS antigen A, anti-La/SS antigen B, and antinuclear antibodies.

CONCLUSIONS

The epidemiology of SS is poorly characterized in Africa. Available data are broadly consistent with those from other populations. Extensive and high-quality research is urgently needed.

In Black Africans with rheumatoid arthritis, ACPA recognize citrullinated fibrinogen and the derived peptides α36-50Cit38,42 and β60-74Cit60,72,74, like in Caucasians

Well documented in Caucasians and Asians, the diagnostic value of anti-CCP2 antibodies has been confirmed in Black African populations. However, autoantibodies to other citrullinated peptides/proteins and their fine specificities have not yet been studied. Here, we show that in Cameroonian patients, anti-citrullinated fibrinogen autoantibodies (AhFibA) are sensitive (73%) diagnostic markers for RA. We also determine that autoantibodies directed to α36-50Cit38,42 or β60-74Cit60,72,74 peptides which bear the immunodominant epitopes of citrullinated fibrin, are present in similar proportions in Black Africans and Caucasians with 25/56 (45%) and 41/56 (73%) positive RA-sera in Cameroonians, respectively. They also account for almost all the AhFibA reactivities since 38/41 (93%) AhFibA-positive sera contain anti-α36-50Cit38,42 and/or anti-β60-74Cit60,72,74 autoantibodies. Finally, HLA-DRB1 SE alleles were associated with higher titres of AhFibA and anti-β60-74Cit60,72,74 autoantibodies. In the genetic and environmental backgrounds of Black Africans, AhFibA are a hallmark of RA like in Caucasians, moreover they recognize the same fibrin epitopes.

Investigation of Caucasian rheumatoid arthritis susceptibility loci in African patients with the same disease

INTRODUCTION

The largest genetic risk to develop rheumatoid arthritis (RA) arises from a group of alleles of the HLA DRB1 locus ('shared epitope', SE). Over 30 non-HLA single nucleotide polymorphisms (SNPs) predisposing to disease have been identified in Caucasians, but they have never been investigated in West/Central Africa. We previously reported a lower prevalence of the SE in RA patients in Cameroon compared to European patients and aimed in the present study to investigate the contribution of Caucasian non-HLA RA SNPs to disease susceptibility in Black Africans.

METHODS

RA cases and controls from Cameroon were genotyped for Caucasian RA susceptibility SNPs using Sequenom MassArray technology. Genotype data were also available for 5024 UK cases and 4281 UK controls and for 119 Yoruba individuals in Ibadan, Nigeria (YRI, HapMap). A Caucasian aggregate genetic-risk score (GRS) was calculated as the sum of the weighted risk-allele counts.

RESULTS

After genotyping quality control procedures were performed, data on 28 Caucasian non-HLA susceptibility SNPs were available in 43 Cameroonian RA cases and 44 controls. The minor allele frequencies (MAF) were tightly correlated between Cameroonian controls and YRI individuals (correlation coefficient 93.8%, p = 1.7E-13), and they were pooled together. There was no correlation between MAF of UK and African controls; 13 markers differed by more than 20%. The MAF for markers at PTPN22, IL2RA, FCGR2A and IL2/IL21 was below 2% in Africans. The GRS showed a strong association with RA in the UK. However, the GRS did not predict RA in Africans (OR = 0.71, 95% CI 0.29 - 1.74, p = 0.456). Random sampling from the UK cohort showed that this difference in association is unlikely to be explained by small sample size or chance, but is statistically significant with p<0.001.

CONCLUSIONS

The MAFs of non-HLA Caucasian RA susceptibility SNPs are different between Caucasians and Africans, and several polymorphisms are barely detectable in West/Central Africa. The genetic risk of developing RA conferred by a set of 28 Caucasian susceptibility SNPs is significantly different between the UK and Africa with p<0.001. Taken together, these observations strengthen the hypothesis that the genetic architecture of RA susceptibility is different in different ethnic backgrounds.

Rheumatic diseases in patients attending a clinic at a referral hospital in Yaounde, Cameroon

BACKGROUND

The spectrum of rheumatic diseases in sub-Saharan Africa remains poorly defined.

OBJECTIVES

To determine the spectrum of rheumatic diseases in Yaounde.

DESIGN

Descriptive cross-sectional study.

SETTING

Rheumatology clinic at the Yaounde General Hospital, Cameroon.

SUBJECTS

Twelve thousand four hundred and ninety four patients were referred to the outpatient department of the Internal Medicine service of the General Hospital of Yaounde over a 12-month period. Of these cases, 536 (9.4%) were diagnosed as belonging to the general class of rheumatic conditions. There were 334 (62.31%) females and 202 (37.69%) males. The mean age was 52.72 +/- 5.3 years.

RESULTS

The 536 cases were further classified as follows: degenerative disease of the spine 196 (36.5%), osteoarthritis of the limbs 110 (20.5%), regional musculo-skeletal disorders 83 (15.5%), arthritis associated with infections 50 (9.3%), chronic inflammatory and connective tissue diseases 44 (8.2%), crystalline arthropathies 32 (5.9%) and miscellaneous (unclassified) rheumatic conditions 21 (4.1%).

CONCLUSION

From these results, we concluded that degenerative disease of the spine and limbs are the most common forms of rheumatic disease in this region. Gout is the most commnon acute inflammatory arthropathy and rheumatoid arthritis the most prevalent arthropathy due to chronic inflammation.

[Bone mineral density in Cameroon women in Yaounde: an echographic study]

AIM

To determine the bone mineral density (BMD) of Cameroonian woman and the importance of primary osteoporosis of the menopausal women.

METHOD

It was a 10 months cross sectional and observational study carried out on voluntary clinically healthy women aged at least 20 years. A complete clinical examination and measurement of the BMD by quantitative ultrasound measurement of the calcaneus was carried out. The BMD was calculated automatically by the apparatus with values in g/cm2 and in T-score.

RESULTS

367 women, mean age 52 year (range 20 and 89) were included in the study. 218 (59.4%) were menopausal. The average bone mineral density was 0.513 g/cm2 (+/- 0.141). The bone minera density reduction was progressive with age with a sharp slope after 70 years. The statistically significant reduction of BMD was associated with: menopause, lower or moderate physical activity, weekly consumption of milk product evaluated at less than the equivalent of a cup of yoghurt, cigarette smoking. Alcohol consumption and obesity had no significant influence on the distribution of BMD. Considering the T-score, 13.6% had osteoporosis, 46.6% osteopenia and 53.4% were normal. In the women of 50 years and above, 17.9% had osteoporosis against 0.6% in women below 50 years while above 70 years, 55.8% had osteoporosis.

CONCLUSION

The BMD of urban Cameroonian women is comparable with that of other women in the world. Osteoporosis is seemingly also present as in the western world, but with relatively less fractures. These results need to be confirmed by studies with larger population size.

Waldenström's disease complicated by recurrent meningococcal arthritis

Meningococcal arthritis is rare. We report a patient in whom a first episode of meningococcal arthritis revealed Waldenström's disease and who experienced a second episode of meningococcal arthritis 8 years later. We suggest that an impaired immune response secondary to Waldenström's disease favored the recurrence of meningococcal arthritis.