Optic neuropathy among a prison population in Papua New Guinea.
OBJECTIVE
To estimate the prevalence of optic neuropathy (ON) among prisoners in a provincial prison in Papua New Guinea, and to explore risk factors for this condition among this population.


METHODS
Cross-sectional observation study of 148 male prisoners aged ≥18 years using an interview-based questionnaire, assessment of visual and nervous system function, ocular examination, and blood analysis (α-tocopherol, β-carotene, lutein, folate, homocysteine, holotranscobalamin II, riboflavin, selenium, thiamin, and vitamins A, B(12) and C). Likelihood of the presence of ON was based on ordered groups determined by weighted combination of optic nerve head appearance and visual dysfunction (acuity, field, color perception). Main outcome measures were prevalence and associations of ON.


RESULTS
Sample prevalence of clinical ON was 10.4% (95% confidence interval [CI], 6.2-16.8). No cases were found of unexplained non-visual nervous system dysfunction, including peripheral neuropathy. Increasing age (p = 0.001), length of current (p = 0.002) and lifetime (p = 0.03) incarceration, and duration of smoking by current smokers (p = 0.001) were associated with increased ON likelihood. However, when age-controlled, the smoking duration association was not maintained (p = 0.6). Prisoners were folate deficient. Adjusting for age and duration of current incarceration, whole blood (p = 0.02) and red blood cell (p = 0.04) folate concentrations were inversely associated with ON likelihood. No association was found for any other assessed demographic, lifestyle or biochemical measure.


CONCLUSIONS
A cluster of ON associated with folate deficiency has been identified. Recommendations for dietary change and micronutrient supplementation have been made.
The Fred Hollows Foundation New Zealand, Auckland, New Zealand.
Benoit
B
Tousignant
Garry
G
Brian
Bernard J
BJ
Venn
Camilla
C
Gould
Robert
R
McKay
Sheila
S
Williams
D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005492:Folic Acid / Q000097:blood; D005494:Folic Acid Deficiency / Q000097:blood / Q000453:epidemiology; D006801:Humans; D014975:Lutein / Q000097:blood; D008297:Male; D009901:Optic Nerve Diseases / Q000097:blood / Q000453:epidemiology*; D010219:Papua New Guinea / Q000453:epidemiology; D015995:Prevalence; D011329:Prisoners / Q000706:statistics & numerical data*; D012307:Risk Factors; D012643:Selenium / Q000097:blood; D011795:Surveys and Questionnaires; D014786:Vision Disorders / Q000097:blood / Q000453:epidemiology; D014801:Vitamin A / Q000097:blood; D014805:Vitamin B 12 / Q000097:blood; D024502:alpha-Tocopherol / Q000097:blood; D019207:beta Carotene / Q000097:blood
D019207:beta Carotene; D014801:Vitamin A; D005492:Folic Acid; D024502:alpha-Tocopherol; D012643:Selenium; D014805:Vitamin B 12; D014975:Lutein