Cardiovascular risk factors and near visual impairment among Congolese older people: EPIDEMCA-FU population-based cohort
Résumé
Objective:
It is recognized that some cardiovascular risk factors (CVRF) are involved in poor ocular health. The deleterious effects are potentially more pronounced among older adults. However, it is unknown whether CVRF are
associated independently or not to Visual Impairment (VI) among African older people while both (CVRF and VI) are very
common in sub-Saharan Africa. Therefore, we investigated the association between CVRF and near VI among
Congolese older people.
Methods: Participants were Congolese older people aged ≥ 65 years included in EPIDEMCA-FU (Epidemiology of
Dementia in Central Africa - Follow-up) population-based cohort carried out from 2011 to 2015. Visual acuity was
assessed at 30 cm using a Parinaud chart. Near VI was defined as having a visual acuity < 20/40. A cohort design was
used taking all CVRF and covariates at baseline and visual acuity at 1st follow-up. Associations were investigated using
multivariate logistic regression.
Results: 549 participants were included in our analyses. Participants median age was 72 years [interquartile range: 68-
78 years] and 331 (60.3%) were females. In total, 378 had near VI (328 had mild/moderate near VI, 38 had severe VI and
12 were blind). Prevalence of near VI was 68.8% [95% Confidence Interval: 64.9% - 72.7%] and higher in males (71.1%;
95%CI: 65.1% - 77.1%) than females (67.4%; 95% CI: 62.3% - 72.4%). Of the CVRF explored, we found that having high
BMI ≥ 25 kg/m2 (adjusted Odds Ratio = 2.31 [95%CI: 1.25 – 4.28]), diabetes (aOR=2.14 [95%CI: 1.07 – 4.29]) and
hypertension (aOR=1.65 [95%CI: 1.03 – 2.66]) were independently associated with near VI. However, after adjustment
on cognitive status, hypertension (full-adjusted OR=1.58 [95%CI: 0.97 – 2.58]) was no longer significantly associated with
VI. There was no interaction between these CVRF. We found no significant association for alcohol consumption
(p=0.541), smoking status (p=0.88), and indirect marker of poor diet (0.33) in our sample.
Conclusion: Prevalence of near VI was high among Congolese older people. High BMI, diabetes, and hypertension were
independently associated to near VI in this population. Our study suggests that these CVRF could represent targets for VI
prevention. However, further studies are required to clarify underling mechanisms because these associations may be
mediated by the presence of ocular conditions/eye diseases.