ORIGINAL COMMUNICATION Risk factors for nightblindness among women of childbearing age in Cambodia RD Semba 1 *, S de Pee 2 , D Panagides 3 , O Poly 4 and MW Bloem 2 1 Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA; 2 Helen Keller International, Asia Pacific Regional Office, Jakarta, Indonesia; 3 Helen Keller International National Office, Phnom Penh, Kingdom of Cambodia; and 4 Ministry of Health, Government of Cambodia, Kingdom of Cambodia Objective: To characterize risk factors for nightblindness among nonpregnant women of childbearing age, a group recently recognized to be at high risk of vitamin A deficiency in some developing countries. Design: Case–control study. Setting: The study included 415 000 households in National Micronutrient Survey of Cambodia conducted in 2000. Subjects: The prevalence of nightblindness among 13 358 nonpregnant women was 2.0%. A total of 328 nonpregnant women with nightblindness were matched by province with 1009 nonpregnant women without nightblindness. Methods: Univariate and multivariate logistic regression models were used to estimate odds ratios (ORs) as estimates of the relative risk of factors associated with nightblindness. Results: In a final model, materials in the wall of the house (OR 1.4, 95% confidence interval (CI) 0.9–2.0), land ownership r0.5 hectares (OR 1.4, 95% CI 1.0–1.9), nightblindness in last pregnancy (OR 44.5, 95% CI 29.2–67.8), parity 43 (OR 1.5, 95% CI 1.0–2.1), diarrhea within the last 2 weeks (OR 1.9, 95% CI 1.3–2.8), maternal body mass index o18.5 (OR 1.8, 95% CI 1.2– 2.7), and lack of consumption of vitamin A-rich animal foods in the last 24 h (1–60 retinol equivalents (RE) OR 1.1 , 95% CI 0.7– 1.6; Z60 RE, OR 0.7, 95% CI 0.4–1.0) were associated with nightblindness among nonpregnant women. Conclusions: Women of childbearing age in Cambodia with low socioeconomic status, low consumption of vitamin A-rich animal foods, a history of nightblindness during the previous pregnancy, parity 43, malnutrition, and diarrhea have a higher risk of nightblindness. Sponsorship: United States Agency for International Development (442-G-00-95-00515–00). European Journal of Clinical Nutrition (2003) 57, 1627–1632. doi:10.1038/sj.ejcn.1601734 Keywords: Cambodia; diarrhea; epidemiology; nightblindness; poverty; vitamin A; women Introduction Vitamin A deficiency is common in many developing countries worldwide (McLaren & Frigg, 2001) and is a major cause of impaired immunity and increased morbidity and mortality from measles, diarrheal disease, tuberculosis, and human immunodeficiency virus infection (Semba, 2001). Nightblindness is an early clinical manifestation of vitamin A deficiency among preschool children (Blankhart, 1967) and pregnant women in developing countries (Dixit, 1966) and has long been known to be associated with infectious diseases (Nylund, 1944). Among preschool children, night- blindness has been associated with increased diarrheal disease morbidity (Khan et al, 1984; Stoll et al, 1985) and tuberculosis (Solon et al, 1978). Nightblindness was asso- ciated with gastrointestinal and genitourinary infections among pregnant women (Christian et al, 1998a). Recently, nightblindness was found to be relatively common among nonpregnant women in Bangladesh (Bloem et al, 1995), suggesting that in some parts of the world, women of childbearing age also comprise a high-risk group for vitamin A deficiency. Although the risk factors for vitamin A deficiency have been well characterized among preschool children and pregnant women, little is known about the epidemiology of vitamin A deficiency among women of childbearing age. The characterization of risk factors for nightblindness among nonpregnant women could help facilitate strategies aimed at preventing vitamin A deficiency in this high-risk group. We Received 14 September 2002; revised 15 December 2002; accepted 17 December 2002 *Correspondence: RD Semba, 550 North Broadway, Suite 700, Baltimore, MD 21205, USA. E-mail: rdsemba@jhmi.edu European Journal of Clinical Nutrition (2003) 57, 1627–1632 & 2003 Nature Publishing Group All rights reserved 0954-3007/03 $25.00 www.nature.com/ejcn