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Infants, preschool children, and women of childbearing age are at the highest risk of vitamin A deficiency. Risk factors for vitamin A deficiency among women are discussed separated in sections 3.1.13. and 3.1.14. The reported age distribution of xerophthalmia among infants and children varies, depending on whether the study population is community-based or based on case reports from hospitals or clinics. In general, community-based surveys suggest that the peak age for xerophthalmia among children is about 4-6 yr of age. For example, among preschool children in Jordan, the prevalence of xerophthalmia was highest between 50 and 60 mo of age for girls and 40 and 70 mo of age for boys (750). In a survey of 1715 children, aged 1-16 yr, in Cebu, Philippines, the overall prevalence of xerophthalmia was 2.7%, and of children aged 1-3, 4-6, 7-9, 10-13, and 14-16 yr, the prevalence of xerophthalmia was 1.4, 4.7, 3.3, 1.8, and 3.4%, respectively (751). In a country-wide survey of 13,450 preschool children in Sri Lanka, the prevalence of Bitot spots among children aged 6-11, 12-23, 24-35, 36-47, 48-59, and 60-71 mo was 0.1, 0.2, 0.8, 1.4, 1.4, and 2.1%, respectively (752). In the lower Shire Valley of Malawi, the highest rates of active xerophthalmia (night blindness, Bitot spots, corneal xerosis, corneal ulceration) were found in children aged 3-5 yr (673). The prevalence of xerophthalmia among children aged 6-72 mo in northern Sudan was highest among children aged 4-6 yr (647). In a survey of 11,378 preschool children in three underserved provinces of the Philippines, the prevalence of xerophthalmia was twice as high for children 6 yr of age compared with children under 2 yr of age (635). In western Yemen, children aged 4-5 yr were at greater risk of xerophthalmia than children younger than 4 yr of age (OR 2.9, 95% CI 1.6-5.4) (726).

In hospital and clinic-based reports, the risk of xerophthalmia is higher among younger children and infants. Younger children are more prone to severe eye disease and are more likely to be brought to the hospital or clinic by their mothers. Studies in the early 20th century provide some insight into the age distribution in severe eye disease. Among 430 cases of keratomalacia seen in Copenhagen from 1909 to 1920, the median age was about

8 mo (48). In a consecutive series of 1149 children seen in a 2-yr period in the mid-1960s in an outpatient clinic in Surabaya, Indonesia, xerophthalmia was most common among children who were 2-4 yr of age (115). Of 162 children with corneal xerosis, corneal ulceration, or keratomalacia seen at Cicendo Eye Hospital, Bandung, Indonesia, between 1977 and 1978, 33% of children admitted were 2 yr of age (285). Of117 children admitted to the same hospital for xerophthalmia between 1981 and 1992, the peak age category of hospitalization was 2-3 yr of age (623).

The presence of vitamin A deficiency among primary school-aged children has not been well characterized, as most surveys of vitamin A deficiency have focused on infants and preschool children. Given the higher prevalence of night blindness and Bitot spots among children aged 4-6 yr in community-based studies, this suggests that the risk of vitamin A deficiency may extend to primary school-aged children. In a survey of 4991 children, aged 0-12 yr, in the Sertão, an arid region of northeast Brazil, the prevalence of Bitot spots was 1% in school-aged children and 0.3% in preschool children (p < .005) (738). A higher prevalence of xerophthalmia has been reported among school-aged children compared with preschool children in Ethiopia (753). Xerophthalmia was reported among individuals up to 19 yr of age in a survey of 149 villages in Bangladesh in 1981 (754). In a study of 1325 children displaced by famine in Ethiopia, the prevalence of Bitot spots was 3.35% among children aged 7-14 yr compared with 0.93% among children aged 0-6 yr (755). Inadequate vitamin A intake and low serum retinol concentrations have also been reported in school-aged children (756,757) and in adolescent girls (758). In some cases, the presence of Bitot spots may not necessarily reflect active vitamin A deficiency, especially among older children. With prolonged vitamin A deficiency, the squamous metaplasia of the conjunctiva may become irreversible, even if the individual has returned to a state of replate vitamin A status.

Among preschool children, boys have often been reported to be at higher risk of xerophthalmia than girls (115,635,639,641,726,747,751,759,760). Boys were at higher risk than girls of having xerophthalmia in northern Sudan (OR 1.70, 95% CI 1.48-1.95) (647), in the Republic of Kiribati (OR 1.32, 95% CI 1.05-1.67) (641), and in western Yemen (OR 2.1, 95% CI 1.2-4.0) (726).

5.3.6. Breastfeeding

Early reports have often linked corneal ulceration and keratomalacia with lack of breastfeeding. Masamichi Mori (1806-1932), in his detailed description of 1511 children with "hikan," or xerophthalmia and keratomalacia in Japan, noted that the condition rarely occurred in children under age 12 mo unless the infant received total or partial artificial feeding instead of breast milk (761). In 1906, Adalbert Czerny (1863-1941) and Arthur Keller (1868-1934) described xerophthalmia among children in Breslau who were fed flour-based preparations as a substitute for milk or breast-feeding, and xeroph-thalmia was part of a syndrome they termed "Mehlnährschaden" that included wasting, poor weight gain, depressed immunity, and increased infections (762). In the late 1930s, hundreds of cases of xerophthalmia were reported among infants and young children in Java who received sweetened condensed milk or skimmed milk instead of breast milk by Maria van Stockum (Otten-van Stockum) (1885-1940) (763) and by J.H. de Haas (764).

In the 1940s, keratomalacia was described among infants in Singapore who were fed sweetened condensed milk, a poor source of vitamin A (765).

Lack of breastfeeding, early cessation of breastfeeding, introduction of vitamin A-poor complementary foods, and rapid weaning are associated with vitamin A deficiency (115,285,747,766-770). In a country-wide survey in Indonesia, breast-feeding was less common among 358 children with Bitot spots compared with matched controls or other normal children (767). In a case-control study of breast-feeding and weaning patterns in Malawi, xerophthalmia was associated with weaning onto porridge, a shorter weaning interval, and early cessation of breast-feeding (769). Another case-control study at a diarrhea treatment center in Dhaka, Bangladesh showed that breastfeeding was protective against xerophthalmia (OR 0.26, 95% CI 0.14-0.49) (770). The frequency of breastfeeding was highly protective against xerophthalmia in Nepal (745). In a case-control study of 666 children with xerophthalmia and 816 children without xeropthalmia in the Republic of Kiribati, current breastfeeding was protective against xerophthalmia (OR 0.30, 95% CI 0.19-0.46) (641).

5.3.7. Infectious Diseases

Vitamin A deficiency is characterized by impaired immune function and increased susceptibility to some infectious diseases. In general, the morbidity of infectious diseases is more severe among individuals with vitamin A deficiency. Diarrheal disease, tuberculosis, measles, whooping cough, pneumonia, Ascaris infection, and human immunodeficiency virus infection are associated with vitamin A deficiency, and in many situations, an episode of disease will precede a case of xerophthalmia.

Diarrheal disease. A history of diarrheal disease is common among children with xerophthalmia (115,285,369,647,722,743,745,747,754,761,771-775). In 1833, the British ophthalmologist Richard Middlemore (1804-1896) observed individuals with cholera around Birmingham who "consequent to an attack of cholera" developed "ulceration or sloughing of the cornea—and suppuration of the eyeball." He noted: "In nearly every instance the disease of the eye occurred as the symptoms of cholera were subsiding" and "sometimes the cornea appeared to ulcerate or slough, without having been preceded by any appreciable amount of inflammation" (776). In Bangladesh, all children with multiple corneal ulcers or keratomalacia had a history of diarrhea in the preceding 4 wk (743). In northern Sudan, a history of diarrhea (three or more loose watery stools within 24 h) in the previous 7 d was associated with xerophthalmia (OR 1.22, 95% CI 0.98-1.53) (647). In lowland Nepal, children were at higher risk of xerophthalmia if they had dysentery for 1 to 6 d in the previous 7 d (OR 2.13, 95% CI 1.02-4.46) or dysentery for >7 d (OR 5.81, 95% CI 1.11-30.58) (745). Previous diarrhea or dysentery was also associated with xerophthalmia in Bangladesh (754). In Ethiopia, the prevalence of diarrhea was twice as high in children with xerophthalmia than among children without xerophthalmia (655). In a random sample of 700 children, aged 0-6 yr, at Saddam Paediatric Hospital in Iraq, xerophthalmia was found in 29% and was associated with diarrheal disease (774). In a study of 400 children, aged 6-59 mo, with acute diarrhea in rural Bangladesh, 7.8% had night blindness and 2.7% had Bitot spots (775). In the Republic of Kiribati, recent diarrhea was associated with xerophthalmia (OR 1.45 95% CI 1.10-1.89 (641).

Measles. The association between measles and vitamin A deficiency has been extensively documented and reviewed in detail elsewhere (598). In 1874, Friedrich Bezold

(1842-1908), a physician in Munich, described keratomalacia in a 5-mo-old infant following an attack of measles (777). Other detailed descriptions were made by the Greek ophthalmologist, Alexios Trantas (1867-1961), in Constantinople at the turn of the century (778,779). These are early examples of many reports of corneal ulceration and keratomalacia associated with acute complicated measles (722,768,780-795). In Bangladesh, nearly 10% of children with active corneal lesions (X2/X3) had a history of measles within the preceding 4 wk (743). In the Republic of Kiribati, a recent history of measles was associated with corneal xerophthalmia (OR 7.73, 95% CI 1.78-33.65) (641).

Respiratory disease. A history of respiratory disease has often been reported in children with xerophthalmia (115,285,673,750) and autopsy series of infants who died with keratomalacia often show evidence of bronchopneumonia (368,369). In longitudinal studies in Indonesia, a previous episode of respiratory disease increased the risk of a child having xerophthalmia (796), and an episode of xerophthalmia increased the risk of subsequently having an episode of respiratory disease (797). Acute measles complicated by lower respiratory infection are associated with xerophthalmia (795). Maternal night blindness has been associated with increased risk in their infants of nasopharyngeal colonization with S. pneumoniae (798).

Tuberculosis. Xerophthalmia is associated with tuberculosis in infants and children, and most of these cases typically consist of infants with marasmus or kwashiorkor who had corneal ulceration or keratomalacia (115,369,751,786,799,800). Sydney Stephenson (1862-1923) described tuberculosis in nearly 20% of the children he saw with keratomalacia in London at the turn of the century (799). There were 3 cases of tuberculosis among 17 autopsies of infants and children with keratomalacia that were conducted by Lewis Sweet (1902-1950) and his colleague H. J. K'ang at Peiping Union Medical College (369). Tuberculosis may be underestimated in its association with vitamin A deficiency among infants and children, given the difficulty of confirming the diagnosis of tuberculosis in this age group.

Other infections. Otitis media has been associated with xerophthalmia in many studies (49,115,368,369,643). Kenneth Blackfan (1883-1941) and S. Burt Wolbach (1880-1954) described cases of otitis media in their autopsy series of infants who had died with keratomalacia in Boston (368). Whooping cough has occasionally been reported in association with xerophthalmia (751,780). Intestinal helminth infections such as ascariasis have been associated with vitamin A deficiency and malabsorption of vitamin A (115,801804), and keratomalacia has been described in association with giardiasis (805). In 1823, the German ophthalmologist Theodor Heinrich Wilhelm Lerche (1791-1847) described an association between intestinal worm infections and night blindness among the general population in St. Petersburg (806). Lerche received his medical degree at the University of Dorpat in 1812 and moved to St. Petersburg, where he noted diarrheal illnesses, helminthiasis, and night blindness, especially around the time of the great fasts (806). Small-pox, which has been eradicated worldwide, was once associated with xerophthalmia (807).

Xerophthalmia is commonly associated with an inadequate intake of dietary vitamin A (49-52,115,285,636,647,744,746-748,751,767,775,808-811). A lower intake of vitamin A from plant sources was associated with a higher risk of night blindness among children in Bogor, Indonesia (808). The intake of vitamin A per head in families was adequate, but there was an unequal distribution of vitamin A-containing foods among members of the household (808). In a case-control study of 466 children, under age 6 yr, with Bitot spots and/or corneal xerophthalmia and matched controls in Aceh, Indonesia, the risk of xerophthalmia increased with less frequent consumption of dark green leafy vegetables (OR 6.4, 95% CI 3.4-12.2), yellow fruits or vegetables (OR 4.6, 95% CI 2.77.7), egg (OR 2.2, 95% CI 1.5-3.3), or meat and fish (OR 2.4, 95% CI 1.5-3.8) (744). Children with xerophthalmia who were younger than 3 yr of age appeared to be a higher risk of dietary imbalance than were older children (744). In northern Bangladesh among children under the age of 9 yr, no consumption of fish, meat, milk, or eggs (OR 4.90, 95% CI 2.03-11.81), yellow fruits (OR 3.90, 95% CI 1.57-9.85), or dark green leafy vegetables (OR 2.50, 95% CI 095-6.47) was associated with an increased risk of night blindness (748).

5.3.9. Home Gardens

In many rural areas in developing countries, home gardens are an important source of plant sources of vitamin A and may provide protection against vitamin A deficiency. In B angladesh, the relative risk of having a child with active corneal lesions (X2/X3) was more than three times greater for households with no garden (743). In the Republic of Kiribati, the presence of a fruit and vegetable garden project was associated with a decreased risk of xerophthalmia (OR 0.70, 95% CI 0.52-0.93) (641).

5.3.10. Malnutrition

It has long been recognized that corneal ulceration and keratomalacia are more common among infants with severe malnutrition, as reflected in numerous case reports and case series from around the world (3,16-18,23,24,49,51,52,113,115,261,285,318,337, 368,369,750,761,762,764,780,784,786,799,800,805,812-884). Community-based studies also show that xerophthalmia is associated with malnutrition (641,745,760). Among 100 malnourished children up to 8 yr of age seen in New Delhi, India, the prevalence of xerophthalmia increased with the severity of malnutrition (885). Keratomalacia has been described in association with pellagra (868), rickets (835), and scurvy (886). Nearly one-third of adults with beriberi in the Philippines had marked impairment of dark adaptation (887). Corneal ulceration was described in an adult with ulcerative colitis who purposely eliminated all fresh fruits and vegetables from her diet (888). A 39-yr-old man presented with bilateral keratomalacia after he had been on a "healthy diet" of brown rice, pulses, and alfafa sprouts for 7 yr, with no animal or dairy products (889). In 1890, the German ophthalmologist Wilhelm Uhthoff (1853-1927) described a large series of adults with alcoholism, poor nutrition, and xerophthalmia (890). Keratomalacia was described in a 57-yr-old German man with alcoholism, wasting, and acute pancreatitis (891). In India, infants fed on soy milk for 10 to 12 wk developed xerophthalmia and keratomalacia (892). At the time, the soy milk product was not fortified with any vitamins (893).

In a study of 213 malnourished children, aged 4-60 mo, in Sudan, 29% had xeroph-thalmia (894). Among children aged 6-35 mo attending a diarrheal treatment center in Dhaka, Bangladesh, the risk of vitamin A deficiency was higher if the child was <60% of the National Center for Health Statistics median of weight-for-age (OR 3.8, 95% CI 1.88.0) (770). The association between xerophthalmia and malnutrition has been observed among preschool children in an urban slum in India (811). In Bangladesh, night blindness was associated with protein energy malnutrition, as assessed by mid-upper arm circum-

jan feb mar april may june july aug sept oct nov dec

Fig. 18. Seasonality of keratomalacia in Germany, 1922. This historical example from Europe is typical of seaonality described in developing countries today. (Reprinted from ref. 831.)

ference (895). A higher prevalence of both wasting and stunting were described among children with xerophthalmia compared to children without xerophthalmia in a community-based survey of Bangladesh (760). In Nepal, xerophthalmia was also associated with stunting and wasting (745). Subclinical vitamin A deficiency was associated with protein energy malnutrition among preschool children in Zaire (896). In the Republic of Kiribati, xerophthalmia was associated with mild wasting (OR 3.07, 95% CI 2.33-4.04), moderate wasting (OR 3.55, 95% CI 2.04-6.18), and severe wasting (OR 3.82, 95% CI 2.73-5.35), where wasting categories were defined as mid-upper arm circumference >10 to <25th percentile, >5 percentile to <10th percentile, and <5th percentile, respectively (641). Lower serum retinol concentrations have been associated with stunting and wasting in studies from Ethiopia (655,656).

5.3.11. Season

The incidence of xerophthalmia can have a seasonal pattern in some parts of the world, and these fluctuations are related to the availability of vitamin A-rich foods and patterns of morbidity related to seasonal infections. In the late nineteenth century when malnutrition and diarrhea were more common in London, the peak of cases of keratomalacia coincided with the peak in the diarrhea cases in July-August (799). The examples of seasonality of xerophthalmia are most dramatic from the past in places where xerophthalmia was widespread. In Germany in 1922, the peak incidence among 30 cases of keratomalacia was in May (831) (Fig. 18). In Tianjin, China, a single peak of xerophthalmia was reported from December through April (897) (Fig. 19), however, in nearby Beijing, the incidence of xerophthalmia was highest in January through March and again in July, with the first peak was attributed to scarcity of green vegetables during the winter, and the second peak was attributed to the appearance of diarrhea and dysentery in the summer

jan feb mar april may june July aug sept oct nov dec

Fig. 19. Seasonality of xerophthalmia in Tianjin, China. (Reprinted from ref. 897.)

jan feb mar april may june July aug sept oct nov dec

Fig. 19. Seasonality of xerophthalmia in Tianjin, China. (Reprinted from ref. 897.)

(369). In Tunisia, cases of xerophthalmia were also reportedly more common at the end of the hot summer and were associated with chronic diarrhea (872). The seasonal incidence of more than 15,000 cases of xerophthalmia among children was examined in four ophthalmic hospitals in India, Indonesia, and Vietnam (898). In Bangalore, India, there were more cases of xerophthalmia seen from April to June, and this coincided with a relative scarcity of green vegetables and milk and with a higher prevalence of summer diarrhea. In Surabaya and Bandung, Indonesia, the incidence of xerophthalmia was highest from about March to September. In Hanoi, Vietnam, there were two periods in which xerophthalmia was highest, from April to June and from October to December (898). In a longitudinal study of 312 children, aged 0-4 yr, in rural West Bengal, the incidence of night blindness and/or Bitot spots had a small peak in November-December and in a larger peak in May-June (899). The prevalence of Bitot spots was highest in the pre-monsoon season in West Bengal (899). In longitudinal field studies in Indonesia, the number of children with corneal involvement in xerophthalmia was highest in March through August (285). Among children admitted to Cicendo Eye Hospital in Bandung, Indonesia, the peak month of admissions was in March, which corresponds to the dry season (623). The periodicity of xerophthalmia in some populations needs to be taken in account when conducting epidemiological surveys of vitamin A deficiency. Xerophthalmia was also reported to increase after crop failure in Russia (900).

5.3.12. Malabsorption

Cystic fibrosis. Cystic fibrosis is an autosomal recessive disease that affects primarily Caucasian populations and is characterized by exocrine pancreatic insufficiency, altered pulmonary mucosal immunity, and other abnormalities affecting the liver, sweat glands, and genitourinary tract (901). Exocrine pancreatic insufficiency causes malabsorption of fat and fat-soluble vitamins such as vitamin A, and problems such as steatorrhea and poor weight gain. Cystic fibrosis is caused by a mutation in the FES1 gene that encodes the cystic fibrosis transmembrane conductance regulator. Individuals with cystic fibrosis are at a high risk of developing vitamin A deficiency because of malabsorption of vitamin A (902). One study of 36 infants less than 2 mo of age in Colorado showed that vitamin A deficiency was present among 21% of those diagnosed with cystic fibrosis by newborn screening (903). There have been many case reports of xerophthalmia associated with cystic fibrosis (904-913). Low plasma vitamin A concentrations and impaired dark adaptation appear to occur frequently in cystic fibrosis, even among clinically stable, eutrophic, and retinol-supplemented adolescents (914). Night blindness and conjunctival xerosis may still occur despite vitamin A-supplementation among adolescents with cystic fibrosis, especially if they have liver disease (909).

Pulmonary exacerbations of cystic fibrosis are associated with an increase in inflammation and a decrease in plasma retinol concentrations (915). Xerophthalmic fundus has been reported in an 18-yr-old girl with cystic fibrosis who developed night blindness (908). Regular monitoring of serum retinol concentrations in individuals with cystic fibrosis has been recommended because vitamin A deficiency may still occur despite vitamin A supplementation (902). Low serum retinol concentrations were reported to have no correlation with pancreatic sufficiency in cystic fibrosis (916). Regular monitoring of serum retinol concentrations and adherence to vitamin A supplementation may help patients with cystic fibrosis avoid problems with night blindness (917,918). A study of vitamin A concentrations in the liver among fifteen patients with cystic fibrosis from 8 to 34 yr of age show that hepatic retinol concentrations decrease with age (919). These findings are suggestive that long-term vitamin A supplementation is unlikely to increase the risk of hypervitaminosis A in patients with cystic fibrosis (919). A transient increase in intracranial pressure, as manifested by a bulging anterior fontanelle, was reported in two 9-mo-old infants with cystic fibrosis and xerophthalmia after receiving high-dose vitamin A (913).

Celiac sprue. Celiac sprue, also known as celiac disease and gluten-sensitive enteropathy, is a condition of the proximal small intestine that is characterized by malabsorption (920,921). The condition is associated with injury to the small intestine after the ingestion of wheat gluten or related rye and barley proteins and improves on treatment with a gluten-free diet. The condition has a genetic predisposition and may occur in one of every 120-300 persons in both Europe and the United States (921). It mostly occurs in Caucasians but has been reported occasionally in other ethnic groups. Abnormal T-cell mediated immune responses against ingested gluten may occur in those that are genetically predisposed together the disease (921). Common clinical manifestations include diarrhea, failure to thrive, and abdominal distention in children, and diarrhea and iron deficiency anemia in adults. Children and adults with celiac disease may have abnormal absorption of oral vitamin A (922). During active sprue, vitamin A absorption is severely impaired, but during remission of disease, the absorption of vitamin A may be satisfactory (923). Plasma retinol concentrations are reduced in patients with sprue compared with normal individuals (924). Keratomalacia was reported in a 64-yr-old man with a history of celiac sprue after he developed persistent diarrhea in spite of adherence to a gluten-free diet (925).

Other conditions. Night blindness associated with vitamin A deficiency has been reported with intestinal bypass surgery for morbid obesity (926-930). In addition to night blindness, conjunctival xerosis (926) and Bitot spots (927) have also been reported after intestinal bypass surgery. Xerophthalmia and keratomalacia have been described in an infant with obstructive biliary cirrhosis (931). Night blindness has been associated with alcoholic liver disease (932-934). Severe protein energy malnutrition is associated with impaired intestinal absorption of vitamin A (935).

5.3.13. Pregnancy

Night blindness has long been recognized among pregnant women, with hundreds of cases reported in the literature (936-961). The requirement for vitamin A increases during pregnancy, and many women may not have adequate intake of vitamin A and subsequently develop night blindness. In general, night blindness is more common in pregnant women from poor families and in association with complications of pregnancy such as hyperemesis, anorexia, diarrhea, and other concomitant infections. In a study conducted in 1889-1892 in Nishne Tagilsk in the Urals, O. Walter noted that night blindness among pregnant women seemed to peak in February through April, and a large proportion indicated that they had repeatedly been night blind during pregnancy (941). At a time when vitamin A deficiency was prevalent in Europe, Theodor Birnbacher and Emanuel Klaften noted that night blindness was more common among pregnant women than nonpregnant women of childbearing age (944), and Birnbacher attributed the night blindness to lack of vitamin A (946). Carsten Edmund (b. 1897) and Svend Clemmesen (b. 1901) in Copenhagen concluded that night blindness in pregnant women was due to vitamin A deficiency because the night blindness was promptly cured after treatment with parenteral vitamin A (947). After margarine was fortified with vitamin A in 1936-1937 in Denmark, they noted a decrease in the number of cases of pregnant women with night blindness (947). Parul Christian has recently brought attention to night blindness during pregnancy as an indicator of vitamin A deficiency (962).

5.3.14. Nonpregnant Women of Childbearing Age

Night blindness has also been reported among nonpregnant women of childbearing age in India (963), Bangladesh (964), Nepal (965), and Cambodia (603). In the 1930s, Adalbert Fuchs reported that night blindness and keratomalacia occurred among lactat-ing women in Mysore, India (966). A strong risk factor for night blindness among women of childbearing age is night blindness during the most recent pregnancy (603). However, it does not appear that vitamin A deficiency during the last pregnancy alone is the main determinant of night blindness, as one might expect that the point prevalence of night blindness would be highest immediately following pregnancy. Instead, the risk of night blindness appears to be consistently high and steady for many months following delivery (Fig. 20), which suggests that there are women who have greater risk overall of night blindness because of poor intake of vitamin A-rich foods (603). Among nonpregnant women in Cambodia, in a final multivariate analysis, risk factors for night blindness included materials of the wall of the house (OR 1.4, 95% CI 0.9-2.0), land ownership >0.5 hectares (OR 1.4, 95% CI 1.0-1.9), night blindness in the last pregnancy (OR 44.5, 95% CI 29.2-67.8), parity >3 (OR 1.5, 95% CI 1.0-2.1), diarrhea within the last 2 wk (OR 1.9, 95% CI 1.3-2.8), maternal body mass index (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 REs, OR 1.1, 95% CI 0.7-1.6, >60 retinol equivalents, OR 0.7, 95% CI 0.4-1.0) (603).

0 to <3 3 to <6 6 to <9 9 to <12 12 to <24 24 to <36 36 to <48 48 to <60

Months Since Delivery of Last Pregnancy

0 to <3 3 to <6 6 to <9 9 to <12 12 to <24 24 to <36 36 to <48 48 to <60

Months Since Delivery of Last Pregnancy

N 1194 1515 1310 1247 3318 2164 1611 979 Fig. 20. Point prevalence of night blindness after delivery among women in Cambodia. (Reprinted from ref. 603.)

5.1.15. Institutionalization

Xerophthalmia has been reported in mental hospitals, prisons, and orphanages where the diet may be inadequate in vitamin A (967-970). In Calcutta, corneal ulceration occurred among prisoners recovering from cholera and was thought to be the result of malnutrition (971). Bitot spots and corneal leucomas were described among inmates of a mental hospital in Mathari, Kenya (969). In Kampala and Luzira Prisons in Uganda in the 1920s, corneal ulceration was observed among inmates who were fed a diet poor in vitamin A (970). No cases of xerophthalmia and corneal ulceration were reported from Mengo Prison, where the inmates were fed four pounds of sweet potato (a rich plant source of vitamin A) each day (970). Xerophthalmia was noted to be common in local prisons in Malawi in the 1980s (Moses Chirambo, personal communication). Medical staff and aid workers who deal with prisoners in developing countries should be aware that the presence of night blindness, Bitot spots, or corneal xerosis among inmates indicate a poor quality diet that is low or devoid of vitamin A-rich foods.

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