Vulnerable newborn types: analysis of subnational, population-based birth cohorts for 541 285 live births in 23 countries, 2000-2021.

OBJECTIVE: To examine prevalence of novel newborn types among 541 285 live births in 23 countries from 2000 to 2021. DESIGN: Descriptive multi-country secondary data analysis. SETTING: Subnational, population-based birth cohort studies (n = 45) in 23 low- and middle-income countries (LMICs) spanning 2000-2021. POPULATION: Liveborn infants. METHODS: Subnational, population-based studies with high-quality birth outcome data from LMICs were invited to join the Vulnerable Newborn Measurement Collaboration. We defined distinct newborn types using gestational age (preterm [PT], term [T]), birthweight for gestational age using INTERGROWTH-21st standards (small for gestational age [SGA], appropriate for gestational age [AGA] or large for gestational age [LGA]), and birthweight (low birthweight, LBW [<2500 g], nonLBW) as ten types (using all three outcomes), six types (by excluding the birthweight categorisation), and four types (by collapsing the AGA and LGA categories). We defined small types as those with at least one classification of LBW, PT or SGA. We presented study characteristics, participant characteristics, data missingness, and prevalence of newborn types by region and study. RESULTS: Among 541 285 live births, 476 939 (88.1%) had non-missing and plausible values for gestational age, birthweight and sex required to construct the newborn types. The median prevalences of ten types across studies were T+AGA+nonLBW (58.0%), T+LGA+nonLBW (3.3%), T+AGA+LBW (0.5%), T+SGA+nonLBW (14.2%), T+SGA+LBW (7.1%), PT+LGA+nonLBW (1.6%), PT+LGA+LBW (0.2%), PT+AGA+nonLBW (3.7%), PT+AGA+LBW (3.6%) and PT+SGA+LBW (1.0%). The median prevalence of small types (six types, 37.6%) varied across studies and within regions and was higher in Southern Asia (52.4%) than in Sub-Saharan Africa (34.9%). CONCLUSIONS: Further investigation is needed to describe the mortality risks associated with newborn types and understand the implications of this framework for local targeting of interventions to prevent adverse pregnancy outcomes in LMICs.

Risk factors and patterns of household clusters of respiratory viruses in rural Nepal.

Viral pneumonia is an important cause of death and morbidity among infants worldwide. Transmission of non-influenza respiratory viruses in households can inform preventative interventions and has not been well-characterised in South Asia. From April 2011 to April 2012, household members of pregnant women enrolled in a randomised trial of influenza vaccine in rural Nepal were surveyed weekly for respiratory illness until 180 days after birth. Nasal swabs were tested by polymerase chain reaction for respiratory viruses in symptomatic individuals. A transmission event was defined as a secondary case of the same virus within 14 days of initial infection within a household. From 555 households, 825 initial viral illness episodes occurred, resulting in 79 transmission events. The overall incidence of transmission was 1.14 events per 100 person-weeks. Risk of transmission incidence was associated with an index case age 1-4 years (incidence rate ratio (IRR) 2.35; 95% confidence interval (CI) 1.40-3.96), coinfection as initial infection (IRR 1.94; 95% CI 1.05-3.61) and no electricity in household (IRR 2.70; 95% CI 1.41-5.00). Preventive interventions targeting preschool-age children in households in resource-limited settings may decrease the risk of transmission to vulnerable household members, such as young infants.

Validation of an obstetric fistula screening questionnaire in rural Nepal: a community-based cross-sectional and nested case-control study with clinical examination.

OBJECTIVE: To validate a symptom-based fistula screening questionnaire and estimate obstetric fistula (OF) prevalence in rural Nepal. DESIGN: Cross-sectional and nested case-control study. SETTING: Sarlahi District, Nepal. POPULATION: Parous, reproductive age women. METHODS: The questionnaire assessed symptoms of vesicovaginal and rectovaginal fistula (VVF and RVF, respectively), stress and urge urinary incontinence (SUI and UUI, respectively), fecal incontinence (FI), and included interviewer observations on the smell and presence of urine and/or stool. All women who screened positive for OF and a randomly selected group of women who screened negative for OF were included in a nested case-control study (one case, four normal controls, and four incontinent controls) and underwent confirmatory clinical examinations. MAIN OUTCOME MEASURES: Clinically confirmed OF, and questionnaire sensitivity (Se) and specificity (Sp). RESULTS: Of the 16 893 women who completed cross-sectional screening, 68 were screened-positive cases. Fifty-five (82%) screened-positive cases, 203 screened-negative normal controls, and 203 screened-incontinent controls participated in the case-control study, which confirmed one case of VVF and one case of both VVF and RVF without any false-negative cases. For VVF, the screening tool demonstrated Se 100% (95% CI 34.2-100.0%), Sp 86.9% (95% CI 83.3-89.9%), and estimated VVF prevalence as 12 per 100 000 (95% CI 3-43); for RVF, it demonstrated Se 100% (95% CI 20.7-100.0), Sp 99.8% (95% CI 98.6-100.0), and estimated RVF prevalence as 6 per 100 000 (95% CI 1-34). CONCLUSIONS: The OF screening questionnaire demonstrated high sensitivity and specificity in this low-prevalence setting. TWEETABLE ABSTRACT: Community-based obstetric fistula screening tool validation study, Nepal, n = 16 893: High Se, Sp & feasibility.

The association of preterm birth and small birthweight for gestational age on childhood disability screening using the Ten Questions Plus tool in rural Sarlahi district, southern Nepal.

CONTEXT: The Ten Questions tool was developed in 1984 as a low-cost, simple screen for childhood disability and referral for diagnosis in low-resource settings, and its use in Nepal has not been previously evaluated. Preterm birth and intrauterine growth restriction are potential risk factors for child disability and loss of developmental potential, but there are few studies examining this relationship from developing settings. OBJECTIVE: To examine the associations of small for gestational age and preterm birth as predictors of Ten Questions Plus positivity. DESIGN, SETTING AND PARTICIPANTS: The Ten Questions Plus questionnaire was administered to caregivers of 680 children between 2 and 5 years of age from August 2007 to March 2008 in rural Sarlahi, southern Nepal. Participants had previously been enrolled in a randomized trial of chlorhexidine cleansing at birth. At 1 month of age, children were then enrolled into a randomized 2 × 2 factorial trial of daily iron and zinc supplementation between October 2001 and January 2006. INTERVENTION: None. MAIN OUTCOME MEASURE: Positive screen on the Ten Questions Plus tool defined as a positive response to one or more questions. RESULTS: Of preterm children, 37 (33.6%) had a positive response to at least one question on the Ten Questions Plus and were considered at risk for disability. One hundred and seventy term children (29.8%) were at risk for disability. CONCLUSIONS: The Ten Questions Plus tool can be used in this rural Nepali setting to identify children at increased risk for mental and physical disability to be targeted for further examination. The prevalence of parent-reported disabilities is high in this population (almost one-third of children); children who are both preterm and small-for-gestational age are at increased risk for motor milestone delay, reported learning difficulty, speech and behavioural problems. Intrauterine growth restriction may affect child development and result in disabilities later in childhood.

Supplementation with vitamin A early in life and subsequent risk of asthma.

Animal models suggest that vitamin A deficiency affects lung development adversely and promotes airway hyperresponsiveness, and may predispose to an increased risk of asthma. We examined the long-term effects of vitamin A supplementation early in life on later asthma risk. In 2006-2008, we revisited participants from two cohorts in rural Nepal who were enrolled in randomised trials of vitamin A supplementation. The first cohort received vitamin A or placebo for <16 months during their pre-school years (1989-1991). The second cohort was born to mothers who received vitamin A, ß-carotene or placebo before, during and after pregnancy (1994-1997). At follow-up, we asked about asthma symptoms and performed spirometry. Out of 6,421 subjects eligible to participate, 5,430 (85%) responded to our respiratory survey. Wheezing prevalence during the previous year was 4.8% in participants aged 9-13 yrs and 6.6% in participants aged 14-23 yrs. We found no differences between the vitamin A supplemented and placebo groups from either trial in the prevalence of lifetime or current asthma and wheeze or in spirometric indices of obstruction (p ≥ 0.12 for all comparisons). Vitamin A supplementation early in life was not associated with a decreased risk of asthma in an area with chronic vitamin A deficiency.

Association between nutritional status and positive childhood disability screening using the ten questions plus tool in Sarlahi, Nepal.

The study was conducted to examine the association between the indicators of malnutrition and disability of children as reported by caregivers. The Ten Questions Plus questionnaire was administered to caregivers of 1,902 children aged 1-9 years, during August 2007-March 2008, in rural Nepal. Height and weight of children were also measured. The main outcome was a positive response to one or more questions. In total, 514 (27%) children had a positive response to at least one question. Moderate stunting [odds ratio (OR)=1.47, 95% confidence interval (CI) 1.02-2.12) and severe (OR=2.39, 95% CI 1.60-3.57) stunting were independently associated with reported delay in sitting, standing, or walking. Severe stunting was also associated with report of delayed learning compared to other children of similar age (OR=2.01, 95% CI 1.27-3.20). Parental report of disability was quite prevalent in this setting, with over a quarter of the sample screening positive. Chronic malnutrition may be associated with delayed motor and mental development.

[Conclusions and recommendations of a WHO expert consultation meeting on iron supplementation for infants and young children in malaria endemic areas]. / Conclusions et recommandations à l'issue de la consultation de l'OMS sur la lutte contre la carence martiale chez le nourrisson et le jeune enfant dans les pays d'endémie palustre.

This article presents the results of an expert consultation meeting aimed at evaluating the safety and public health implications of administering supplemental iron to infants and young children in malaria-endemic areas. Participants at this meeting that took place in Lyon, France on June 12-14, 2006 reached consensus on several important issues related to iron supplementation for infants and young children in malaria-endemic areas. The conclusions in this report apply specifically to regions where malaria is endemic.

Indicators of skin barrier integrity among newborns massaged with mustard oil in rural Nepal.

OBJECTIVE: The objective of this study was to determine the skin barrier changes during postnatal month 1 among infants receiving routine mustard oil massage in the humid conditions of rural Nepal. STUDY DESIGN: This was an observational study among 500 live-born neonates receiving mustard oil massage. Skin integrity such as erythema, rash, dryness, skin pH, stratum corneum protein concentration and transepidermal water loss was measured on days 1, 3, 7, 14 and 28. RESULTS: Erythema and rash increased (worsened) during weeks 1 and 2, then decreased over weeks 3 and 4. Skin pH (6.1±0.5 to 5.0±0.6) and stratum corneum protein (16.6±7.9 to 13.5±5.9 µg cm-2) decreased. Transepidermal water loss increased from 33.2±23.5 to 43.0±24.5 g m-2 h-1 at day 28. Skin pH and stratum corneum protein were higher for early versus late premature infants. CONCLUSION: Premature and full-term skin condition was generally poor especially during the first 2 weeks, improving thereafter. Maturational changes were evident.

Relationship between the surrogate anthropometric measures, foot length and chest circumference and birth weight among newborns of Sarlahi, Nepal.

BACKGROUND: Classification of infants into low birth weight (LBW, <2500 g) or very low birth weight (VLBW, <2000 g) categories is a crucial step in targeting interventions to high-risk infants. OBJECTIVE: To compare the validity of chest circumference and foot length as surrogate anthropometric measures for the identification of LBW and VLBW infants. SUBJECTS AND SETTING: Newborn infants (n=1640) born between March and June 2004 in 30 Village Development Committees of Sarlahi district, Nepal. DESIGN: Chest circumference, foot length and weight (SECA 727, precise to 2 g) of newborns were measured within 72 h after birth. The sensitivity, specificity and predictive values for a range of cutoff points of the anthropometric measures were estimated using the digital scale measurements as the gold standard. RESULTS: Among LBW infants (469/1640, 28.6%), chest circumference measures <30.3 cm were 91% sensitive and 83% specific. Similar levels of sensitivity for foot length were achieved only with considerable loss of specificity (<45%). Foot length measurements <6.9 cm were 88% sensitive and 86% specific for the identification of VLBW infants. CONCLUSION: Chest circumference was superior to foot length in classification of infants into birth weight categories. For the identification of VLBW infants, foot length performed well, and may be preferable to chest circumference, as the former measure does not require removal of infant swaddling clothes. In the absence of more precise direct measures of birth weight, chest circumference is recommended over foot length for the identification of LBW infants.

Epidemiology of anemia among 4- to 17-month-old children living in south central Nepal.

OBJECTIVE: To describe the distribution of hemoglobin and prevalence of anemia in Nepali children living in the Terai region by potential risk factors for deficiency. DESIGN: This was a cross-sectional, community-based study of baseline characteristics of children enrolled in a randomized, placebo-controlled clinical trial between January and March 2002. Participants were weighed and measured and had their blood drawn. Their mothers contributed demographic, morbidity, and feeding data. SUBJECTS: There were 569 4- to 17-month-old children. Statistical models were based on 490 children. RESULTS: Anemia was prevalent: 58% of the children had a hemoglobin <105 g/l. Iron-deficiency anemia (anemia with erythrocyte protoporphyrin (EP) > or =90 micromol/mol heme) was present in 43% of the children. Severe anemia was rare: less than 2% of the children had a hemoglobin <70 g/l. The mean (s.d.) hemoglobin concentration was 101 (12.5) g/l. Stunting and wasting were prevalent: 30.8% were stunted (length-for-age Z-score <-2) and 18.1% were wasted (weight-for-length Z-score <-2). Bivariate analyses revealed that age, caste, socioeconomic status, dietary diversity, stunting, and underweight were associated with hemoglobin concentration and/or anemia. In multivariate models with and without EP, age and caste were found to be strong predictors of both hemoglobin concentration and anemia. CONCLUSIONS: Anemia and iron deficiency increased strongly with age and low-caste status among the study children. The data reveal the importance of targeting interventions to children in the first year of life before they become anemic and iron deficient.

Development of clinical sign based algorithms for community based assessment of omphalitis.

BACKGROUND: In developing countries, newborn omphalitis contributes significantly to morbidity and mortality. Community based identification and management of omphalitis will require standardised clinical sign based definitions. OBJECTIVE: To identify optimal sign based algorithms to define omphalitis in the community and to evaluate the reliability and validity of cord assessments by non-specialist health workers for clinical signs of omphalitis. DESIGN: Within a trial of the impact of topical antiseptics on umbilical cord infection in rural Nepal, digital images of the umbilical cord were collected. Workers responsible for in-home examinations of the umbilical cord evaluated the images for signs of infection (pus, redness, swelling). Intraworker and interworker agreement was evaluated, and sensitivity and specificity compared with a physician generated gold standard ranking were estimated. RESULTS: Sensitivity and specificity of worker evaluations were high for pus (90% and 96% respectively) and moderate for redness (57% and 95% respectively). Swelling was the least reliably identified sign. Measures of observer agreement were similar to that previously recorded between experts evaluating subjective skin conditions. A composite definition for omphalitis that combined pus and redness without regard to swelling was the most sensitive and specific. CONCLUSIONS: Two sign based algorithms for defining omphalitis are recommended for use in the community. Focusing on redness extending to the skin around the base of the stump will identify cases of moderate and high severity. Requiring both the presence of pus and redness will result in a definition with very high specificity and moderate to high sensitivity.

Measurement of blood loss at childbirth and postpartum.

OBJECTIVE: To accurately measure blood loss during childbirth in a developing country. METHOD: The alkaline hematin technique was used to quantify blood lost during delivery and 24 h postpartum in 158 women in Pemba Island, Zanzibar. RESULT: Women were found to lose less blood during childbirth and 24 h postpartum than previously reported. Compared with laboratory values, nurse-midwives approximated blood loss accurately (mean difference, i.e., mean underestimation by nurse-midwives, 4.90 mL); however, their imprecision was greater for higher laboratory values. CONCLUSION: This study may prompt further investigation, as no comparable data exist for developing countries where maternal mortality is high and severe anemia prevalent.

Chronic lymphocytic leukemia and acquired disorders affecting the immune system: a case-control study.

The relationship of a number of subacute or chronic infectious diseases, connective tissue or autoimmune disorders, allergic conditions, and surgical excision of lymphoid tissue with chronic lymphocytic leukemia (CLL) was examined in a case-control study involving 342 cases and 342 matched controls. In both analyses of all matched pairs and those pairs in which both subjects were respondents, no statistically significant association was found between a history of subacute viral infections or subacute and chronic bacterial infections and CLL. Connective tissue or autoimmune disorders also were found not to be associated with CLL. Examination of the association between several allergic conditions and CLL suggested a protective effect as did a "dose-response" analysis, although none of the individual disorders showed a statistically significant relationship; however, a test for linear trend was significant (P = .04). Similarly, examination of the relationship between surgical excision of lymphoid tissue in several anatomic locations and CLL showed a protective effect, statistically significant for tonsillectomy-adenoidectomy (odds ratio = 0.69; 95% confidence interval = 0.48, 0.98). A statistically significant negative dose-response relationship, substantiating the protectiveness of the effect, was found.

Incidence of aplastic anemia in a three county area in South Carolina.

An apparent cluster of four aplastic anemia (AA) cases in teenagers residing in a small South Carolina town was further investigated. Incidence of AA in all age groups in a surrounding three county area (TCA) over a 12-year time interval was determined and compared with AA incidence rates in Baltimore, representing the only known population based United States incidence data. The same general age-specific incidence pattern (based on 27 cases in the TCA and 118 in Baltimore) was found in the two areas, both overall and for the four race-sex groups. Although based on small numbers, nonwhite average annual age-adjusted rates for males and females were higher in the TCA (6.8 and 13.7 per million) than in Baltimore (4.7 and 7.3). For whites, TCA rates were 11.7 and 5.4 (for males and females) and Baltimore rates were 7.1 and 5.4. The differences for non-whites in the two areas may indicate a greater prevalence of risk factors for AA in the TCA than in Baltimore, but the small numbers of cases and the lack of comparable data from other areas of the country, together with the possibility of misdiagnosis of the disease, make definitive conclusions impossible.

Undetected eye disease in a primary care clinic population.

BACKGROUND: Population-based data have indicated that a significant proportion of persons with undiagnosed ocular disease in the community are regular users of general medical services. This, combined with the high prevalence of chronic medical disorders known to be risk factors for ocular disease in such clinics, makes them an attractive site for screening. METHODS: The prevalence of ocular disease was estimated in a sample of 405 general medicine patients attending an adult primary care clinic in an urban teaching hospital. RESULTS: Overall, 205 (50.6%) of 405 patients were found to have clinically important ocular pathology. One third of those affected (n = 68) were unaware of their eye disease, and 26% (n = 18) of these 68 patients required immediate medical or surgical intervention. Patients 65 years or older (odds ratio [OR], 1.76), in fair or poor general health (OR, 1.78), with diabetes mellitus (OR, 2.07), or with self-reported fair or poor vision (OR, 3.03), were at increased risk for the presence of ocular disease. Among patients with eye disease, those who had no insurance coverage for eye care (OR, 3.45), those who had not had an eye examination during the previous 2 years (OR, 4.03), and those whose last eye examination was performed by an optometrist (OR, 7.25, reference ophthalmologist) were more likely to not be aware of their eye disease. CONCLUSIONS: Our results underscore the importance of screening for ocular disease in primary health care settings, especially for patients who are older than 65 years, are in poor health, report poor vision, have had infrequent eye examinations, or have inadequate insurance coverage for eye care.

Dry eye and dry mouth in the elderly: a population-based assessment.

BACKGROUND: Symptoms of dry eye and dry mouth are common in the elderly and are often debilitating. Previous research on small populations has been inconsistent regarding the contribution to sicca symptoms of autoimmune markers, medication use, and other factors. The objective of this study was to determine the population prevalence of symptoms of dry eye and dry mouth and to evaluate possible risk factors. METHODS: This is a population-based study of 2481 individuals, aged 65 to 84 years, residing in Salisbury, Md, and identified by the Health Care Financing Medicare database. The main outcome measures included information on sicca symptoms, medical history, medication use, and joint examination results collected in a standardized manner. Autoimmune status was assessed in 1200 individuals by measuring antinuclear antibody, rheumatoid factor, and autoantibodies to the soluble nuclear antigens Ro/SS-A and La/SS-B by double immunodiffusion. RESULTS: Approximately 27% of the population reported dry eye or dry mouth symptoms to be present often or all the time and 4.4% reported both. The prevalence of dry mouth (but not dry eye) symptoms increased with age, female sex, and white race. No association of sicca symptoms was found with rheumatoid arthritis, smoking, alcohol consumption, reproductive hormonal status, or the presence of autoantibodies. A strong, dose-response relationship was observed between sicca symptoms and the use of certain medication classes. The proportion of the population prevalence of sicca symptoms attributable to the use of drying medications was estimated at 62% for dry eye and dry mouth and 38% for dry eye or dry mouth symptoms. CONCLUSIONS: Sicca symptoms are common in the elderly, and medication side effects appear to be a major underlying factor. Our results do not indicate an association between autoimmune status and sicca symptoms and do not support immunologic testing in persons with sicca symptoms in the absence of other important systemic features.

An apparent cluster of aplastic anemia in a small population of teenagers.

Four teenagers with severe aplastic anemia, initially diagnosed and evaluated over a seven-year period at The Johns Hopkins Bone Marrow Transplant Unit, Baltimore, were residents of the same small town in South Carolina. Estimated annual incidence for that age group in the town, based on the four cases, was 100 times the expected rate. All four of the teenagers had attended one of two junior high schools. An exploratory survey of all high-school students, comparing risk factors of those who had attended the "affected" junior high school with those who had attended the "unaffected" junior high school, showed no associations with exposure to glue, paint or varnishes, pesticides, history of hepatitis or infectious mononucleosis, or use of chloramphenicol or other suspected drugs. Weak associations were found between the affected junior high school and employment in the textile industry and in agriculture (specifically peach orchards).

Xerophthalmia and growth in preschool Indonesian children.

Approximately 4000 preschool children in West Java, Indonesia, were examined for xerophthalmia and weighed and measured at 3-mo intervals from March 1977 to December 1978. Children recovering from xerophthalmia over a 3-mo interval gained an average of 124 g (95% CI 42-206) more over 3 mo than normal children. Their height gain was similar to normal children's. Children who developed xerophthalmia during a 3-mo period gained 199 g (95% CI 114-313) less and grew 0.28 cm (95% CI 0.12, 0.44) less than their normal peers. Children with chronic xerophthalmia gained 120 g (95% CI 49-191) less and grew 0.21 cm (95% CI 0.05-0.37) less than normal children. These data suggest that linear and ponderal growth is adversely affected by chronic and incident xerophthalmia, but that catch-up ponderal growth is experienced by children recovering from xerophthalmia.

Epidemiology of iron deficiency anemia in Zanzibari schoolchildren: the importance of hookworms.

Anemia is estimated to affect one-half of school-age children in developing countries. The school years are an opportune time to intervene, and interventions must be based on sound epidemiologic understanding of the problem in this age group. We report on the distribution of iron deficiency and anemia across age, sex, anthropometric indexes, and parasitic infections in a representative sample of 3595 schoolchildren from Pemba Island, Zanzibar. Iron status was assessed by hemoglobin, erythrocyte protoporphyrin (EP), and serum ferritin concentrations from a venous blood sample. Overall, 62.3% of children were anemic (hemoglobin < 110 g/L), and 82.7% of anemia was associated with iron deficiency. The overall prevalence of iron-deficient erythropoiesis (EP > 90 mumol/mol heme) was 48.5%, and the prevalence of exhausted iron stores (serum ferritin < 12 micrograms/L) was 41.3%. In bivariate analyses, iron status was slightly better in girls than in boys, and was better in children aged 7-11 y than in those older or younger. Hemoglobin but not EP or serum ferritin concentrations were lower in stunted children. Infection with malaria, Trichuris trichiura, Ascaris lumbricoides, and hookworms were all associated with worse iron status; the association with hookworms was strongest by far. In multivariate analyses, hookworm infection intensity was the strongest explanatory variable for hemoglobin, EP, and serum ferritin. Sex, malarial parasitemia, A. lumbricoides infection, and stunting were also retained in the multivariate model for hemoglobin. Twenty-five percent of all anemia, 35% of iron deficiency anemia, and 73% of severe anemia were attributable to hookworm infection; < 10% of anemia was attributable to A. lumbricoides, malaria infection, or stunting. We conclude that anthelminthic therapy is an essential component of anemia control in schoolchildren in whom hookworms are endemic, and should be complemented with school-based iron supplementation.

Effects of the Zanzibar school-based deworming program on iron status of children.

We evaluated the effects of the Zanzibar school-based deworming program on the iron status of primary school children. Parasitologic and nutritional assessments were carried out at baseline, 6 mo, and 12 mo in 4 nonprogram schools (n = 1002), 4 schools in which students received twice-yearly deworming (n = 952), and 4 schools in which students received thrice-yearly deworming (n = 970) with 500 mg generic mebendazole. Schools were randomly selected for evaluation and allocated to program groups. Relative to no treatment, thrice-yearly deworming caused significant decreases in protoporphyrin concentrations and both deworming regimens caused marginally significant increases in serum ferritin concentrations. The average annual changes in protoporphyrin concentrations were -5.9 and -23.5 micromol/mol heme in the control and thrice-yearly deworming groups, respectively (P < 0.001). The average changes in ferritin concentration were 2.8 and 4.5 microg/L, respectively (P = 0.07). Deworming had no effect on annual hemoglobin change or prevalence of anemia. However, the relative risk of severe anemia (hemoglobin < 70 g/L) was 0.77 (95% confidence limits: 0.39, 1.51) in the twice-yearly deworming group and 0.45 (0.19, 1.08) in the thrice-yearly deworming group. The effects on prevalence of high protoporphyrin values and incidence of moderate-to-severe anemia (hemoglobin < 90 g/L) were significantly greater in children with > 2000 hookworm eggs/g feces at baseline. We estimate that this deworming program prevented 1260 cases of moderate-to-severe anemia and 276 cases of severe anemia in a population of 30,000 schoolchildren in 1 y. Where hookworm is heavily endemic, deworming programs can improve iron status and prevent moderate and severe anemia, but deworming may be needed at least twice yearly.