Nigeria Blindness Survey had indicated that Igbo ethnic group had a higher risk of developing glaucoma just as men and unmarried people in Nigeria.
The experts found that male gender, ethnicity, and deprivation were strongly associated with blindness, and as such services for glaucoma need to improve in Nigeria, focusing on poor communities and men.
The survey also found increasing age, Igbo and Yoruba ethnic groups and illiteracy were linked to the disease. Also, greater severity of hypertension and being underweight were factors associated with glaucoma.
Nigeria Blindness Survey to explore risk factors for Open-angle glaucoma (OAG) among adults above 40 years examined 13,591 people in 305 clusters in Nigeria between January 2005 and June 2007. The 2016 study was published in the BMC Ophthalmology.
Open-angle glaucoma (OAG) is the most prevalent type of glaucoma in Africa and a leading cause of blindness and visual impairment. Glaucoma is the second-leading cause of blindness after cataract.
For the cross-sectional study of risk factors for OAG, the researchers considered socio-demographic (age, gender, ethnic group, literacy and place of residence); biophysical (presence of hypertension, severity of hypertension, systolic blood pressure [SBP], diastolic blood pressure [DBP], and body mass index [BMI]); as well as ocular (eye) factors such as intraocular pressure (IOP).
They found that men with OAG were significantly older than women with OAG. Higher proportions were of the Yoruba or Igbo ethnic group, illiterate and with hypertension and low BMI (underweight).
Increasing age was positively associated with OAG as was being male. There was a six per cent higher likelihood of OAG with each increasing year of age.
Also, Igbo and Yoruba ethnic groups, being illiterate, hypertension and greater severity of hypertension, low BMI (underweight), longer ocular axial length, higher IOP were also positively associated with OAG.
The Urhobo had the lowest likelihood of OAG, while the Kanuri and Igbo, the highest. The Igbo ethnic group had a 73 per cent higher likelihood of OAG than the Hausa (reference group); and when adjusted for gender, Igbo men were 2.5 times more likely to have OAG than Hausa men.
The study did not find a significant difference in risk for OAG in urban compared to rural population; also its possible associations with hypertension or diabetes were not important.
Hypertension was also associated with OAG, with moderate and severe hypertension having stronger and significant association with OAG. Also, lower BMI was associated with 60 per cent greater likelihoods of OAG and the chances decreased with increasing body weight.
The researchers’ reason that Igbos were most at risk of developing glaucoma, imply that the Igbos have thinner corneas.
In 2013, it was estimated that there were 64.3 million people aged 40 to 80 years with glaucoma worldwide. But this was projected to increase to 76.0 million by the year 2020 and 111.8 million in 2040.