Serum Retinol and Xerophthalmia Among a Prison Population in Papua New Guinea

Abstract

Purpose: 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.

Keywords::

• Nyctalopia
• Papua New Guinea
• Prisoners
• Retinol
• Vitamin A deficiency (VAD)
• Vitamin A deficiency disorder (VADD)
• Xerophthalmia

ACKNOWLEDGMENTS

The authors thank Carmel Williams, Tom Schaefer, Louisa Semmons, Sanya Baker, Janie Elliott, Brenda Jolliffe, Jade Marshall, Clement Manineng, Vincent Atua, Divine Word University student health extension officers and Modilon General Hospital Eye Unit nurses who participated in data collection, and the Papua New Guinea Institute of Medical Research for their help. The authors acknowledge Stephen Demok, whose clinical observations gave rise to this investigation, and the authorities at Beon Prison, the Department of Correctional Services and the National Department of Health for their cooperation.

Financial Support: The design, implementation and analysis of this study were financially supported by the New Zealand Agency for International Development (NZAID) through the Kaihono hei Oranga Hapori o te Ao Partnerships for International Community Development scheme (KOHA-PICD), the Department of Human Nutrition of the University of Otago, and The Fred Hollows Foundation New Zealand.

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the article.