title: Serum retinol and xerophthalmia among a prison population in Papua New Guinea.
abstract: OBJECTIVE
  To estimate the prevalence of vitamin A deficiency (VAD) and one of its clinical manifestations, xerophthalmia, and examine the predictive value of nyctalopia and ocular signs for serum retinol concentrations among a prison population in Papua New Guinea.
  
  
  METHODS
  A cross-sectional study of 148 prisoners and 9 guards; all males aged ≥18 years. Interview-based questionnaire; ocular examination; serum retinol concentration determination.
  
  
  RESULTS
  Two guards had marginal (retinol <1.05-≥0.70 µmol/L) VAD. For prisoners: mean retinol was 0.84 ± 0.49 µmol/L; 43.9% (95% CI 35.9, 52.2) had VAD (retinol <0.70 µmol/L); 9.6% (95% CI 5.1, 17.0) self-reported nyctalopia prior to, and 36.1% (95% CI 27.7, 45.5) after incarceration; 10.9% (95% CI 6.7, 17.0) exhibited at least one sign of xerophthalmia (2 had fundus changes; all 4 with more than conjunctival xerosis alone had severe [<0.35 µmol/L] retinol deficiency). Prisoners with ocular signs were more likely than those without to have VAD (OR 10.4; 95% CI 2.5, 70.3; P < 0.001) and severe retinol deficiency (OR 19.1; 95% CI 5.5, 77.2; P < 0.001). Positive (PPV) and Negative (NPV) Predictive Values: of nyctalopia for any (PPV 62.9%; NPV 32.8%) and severe (PPV 25.7%; NPV 85.9%) retinol deficiency; of ocular signs for any (PPV 93.3%; NPV 38.2%) and severe (PPV 73.1%; NPV 87.8%) retinol deficiency, and VAD (PPV 86.5%, NPV 38.2%).
  
  
  CONCLUSIONS
  VAD and xerophthalmia were present in this prison population. There may be VAD in the wider community. The former needs remedy and the latter deserves investigation. Self-reported nyctalopia was not a useful indicator of retinol deficiency. Absence of ocular signs was unhelpful for ruling out VAD.
authors: The Fred Hollows Foundation New Zealand, Auckland, New Zealand. grbrian@tpg.com.au
authors: Garry
authors: G
authors: Brian
authors: Benoit
authors: B
authors: Tousignant
authors: Bernard J
authors: BJ
authors: Venn
authors: Robert
authors: R
authors: McKay
authors: Camilla
authors: C
authors: Gould
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009755:Night Blindness / Q000453:epidemiology; D010219:Papua New Guinea / Q000453:epidemiology; D010865:Pilot Projects; D011330:Prisons / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D014801:Vitamin A / Q000097:blood*; D014802:Vitamin A Deficiency / Q000453:epidemiology*; D014985:Xerophthalmia / Q000097:blood / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D014801:Vitamin A