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Biomedical subjects

R E Black

Publications and source records attributed to R E Black.

At least 19 recordsLinked to original sources
PubMed1997

Asymptomatic and symptomatic cryptosporidiosis: their acute effect on weight gain in Peruvian children.

This study investigated whether a child's first infection with Cryptosporidium parvum had an acute effect on weight gain. Specifically, the authors compared monthly rates of weight gain between C. parvum-infected and noninfected children. Over a 2-year period (1989-1991), a cohort of Peruvian children aged 0-3 months at recruitment were followed twice weekly for assessment of daily diarrheal status, weekly for C. parvum stool examinations, and monthly for anthropometric measurements. Data on 207 children permitted the authors to examine the effect of C. parvum infection on weight gain. During the 2-year study period, 45% (94/207) of the children became infected with C. parvum for the first time. Weight gain intervals in 57 of the 94 infected children met criteria for analysis. Of these, 63 percent (36/57) were asymptomatic (i.e., had no diarrhea). On average, children with symptomatic cryptosporidiosis gained (i.e., grew) 342 g less (95% confidence interval 167-517) during the first month of infection than did children without diarrhea who were not yet infected. The effect of asymptomatic cryptosporidiosis was less severe: On average, children with asymptomatic infection gained 162 g less (95% confidence interval 27-297) during the first month of infection than did children without diarrhea who were not yet infected. Symptomatic cryptosporidiosis retarded weight gain more than did asymptomatic cryptosporidiosis, but the latter was twice as common. Since asymptomatic cryptosporidiosis is more prevalent, it may have more of an overall adverse effect on child growth in the community than symptomatic cryptosporidiosis.

Acute Disease↗
PubMed1997

The effect of malnutrition on the risk of diarrheal and respiratory mortality in children < 2 y of age in Cebu, Philippines.

The effects of nutritional status on diarrheal and acute lower respiratory infection (ALRI) mortality in children < 2 y of age were examined by using data from a 1988-1991 longitudinal study of 9942 children in Metro Cebu, Philippines. Cox regression methods were used to study the strengths of the associations, possible interactions with birth weight and breast-feeding status, and the effect of additional confounding factors. Nutritional status as measured by weight-for-age was a significant risk factor for both ALRI and diarrheal mortality in the first 2 y of life. Poor nutritional status resulted in a 1.6-fold increased risk of diarrheal mortality for each one-unit decrease in weight-for-age Z score. For ALRI mortality, a one-unit decrease in weight-for-age Z score resulted in a 1.7-fold increase in risk, and for mortality associated with ALRI and diarrhea combined, the relative risk was 2.0. This study provides further evidence that malnutrition is a major determinant of mortality in very young children and it is one of the first longitudinal studies to estimate the magnitude of the effect on cause-specific mortality associated with nutritional status.

Acute Disease↗
PubMed1996

Effect of not breastfeeding on the risk of diarrheal and respiratory mortality in children under 2 years of age in Metro Cebu, The Philippines.

The effects of not breastfeeding on mortality due to diarrhea and acute lower respiratory infection (ALRI) in children under 2 years of age were examined using data from a 1988-1991 longitudinal study of 9,942 children in Metro Cebu, The Philippines. Cox regression methods were used to study the magnitude of the risks, possible interactions with birth weight and nutritional status, and the effect of additional confounding factors. Not breastfeeding had a greater effect on diarrheal mortality than on ALRI mortality. In the first 6 months of life, failing to initiate breastfeeding or ceasing to breastfeed resulted in an 8- to 10-fold increase in the rate of diarrheal mortality. The rate of mortality associated with both ALRI and diarrhea was increased nearly six times by not breastfeeding, but the rate of ALRI mortality alone was not increased. The data also suggested that the risk of mortality associated with not breastfeeding was greater for low birth weight infants and infants whose mothers had little formal education. After age 6 months, the protective effects of breastfeeding dropped dramatically. These findings underscore the importance of promoting breastfeeding, especially during the first 6 months of life, and of targeting high risk groups such as low birth weight babies and those of low socioeconomic status.

Adult↗
PubMed1996

Immunogenicity, safety and protective efficacy of one dose of the rhesus rotavirus vaccine and serotype 1 and 2 human-rhesus rotavirus reassortants in children from Lima, Peru.

In a four cell trial, a single 10(4) plaque-forming unit dose of rhesus rotavirus (RRV) vaccine (serotype G3), a human rotavirus-rhesus rotavirus reassortant vaccine with serotype G1 specificity, a similar vaccine with serotype G2 specificity, or a placebo was administered with buffer orally at 2 months of age to 800 Peruvian infants. Only the RRV vaccine was associated with a febrile response (< 38 degrees C) that occurred in 9% of the infants on day 4 after vaccination. Diarrhea or other side-effects were not associated with administration of vaccine. Vaccine strains were shed by only 12-18% of the infants as determined by examination of a single stool specimen obtained on days 4 or 5 after vaccination. Fifty per cent of vaccines developed an IgA ELISA seroresponse; however, a serotype-specific seroresponse by plaque reduction neutralization was demonstrated in < 20% of the participants against each of the three candidate vaccine strains. Vaccine efficacy was evaluated by twice-weekly home surveillance for diarrheal diseases during 24 months post-immunization. Rotavirus diarrheal episodes were identified by ELISA. Only the RRV vaccine had a significant protective efficacy (29%, p = 0.03, chi-square test) against rotavirus diarrhea. Analysis of vaccine efficacy against rotavirus episodes of any severity in which no other enteropathogen was isolated showed a trend towards higher vaccine efficacy. In addition, a similar trend was observed in rotavirus-only episodes in which there was some degree of dehydration or when health services were utilized. Serotype G1 or G2 rotavirus strains were most prevalent during surveillance. Neither serotype G1 or serotype G2 vaccines were protective against serotype 1 or 2 rotavirus diarrhea, respectively. The serotype G2 vaccine was 84% protective against serotype 1 and 2 dehydrating rotavirus diarrhea in the small numbers of individuals evaluated. We conclude that one dose of 10(4) p.f.u. of the RRV, serotype G1, or serotype G2 rotavirus vaccine failed to induce either an adequate serotype-specific seroresponse or serotype-specific protection in children immunized at 2 months of age. Only the RRV vaccine induced a low level of protection against rotavirus diarrhea mainly of serotype G1 specificity. Future studies need to explore whether higher vaccine dose and/or more than one dose would increase the immunogenicity and efficacy of the rotavirus vaccine, especially in developing countries with a high level of baseline rotavirus antibodies.

Diarrhea, Infantile↗
PubMed1996

Feeding practices and growth among low-income Peruvian infants: a comparison of internationally-recommended definitions.

BACKGROUND: Data from a longitudinal study of 153 low-income Peruvian infants were used to assess the relationship between internationally-recommended definitions of feeding practices and infants' monthly weight gain and weight status at 12 months. METHODS: Infants were classified into feeding categories using monthly reported data. Analysis of variance was used to assess the relationship between reported usual feeding practices and growth. Reported breastfeeding practices were compared to observed breastfeeding practices and to weighted breast milk intakes to determine the validity of recommended breastfeeding definitions. RESULTS: Breastfed infants who consumed non-human milks during the first month of life gained less weight during that month (P < 0.002) than exclusively and predominantly breastfed infants. Reported daily nursing frequency was associated with observed nursing frequency and breast milk energy intake (P < 0.05) for infants < 9 months old. Patterns of growth varied according to early diets. Infants who consumed breast milk and non-human milks and those who were fully weaned by 4 months were more likely to be underweight at 12 months than other infants. Infants classified as token breastfeeders ( < or = 3 times/24 hours) from 0 to 120 days had monthly gains that were similar to those of fully weaned infants. CONCLUSIONS: Infants feeding definitions should 1) continue to differentiate exclusively breastfed infants from other infants who are almost exclusively or predominantly breastfed; 2) distinguish partially breastfed infants who consume only non-breastfeeding frequency or the % of their total daily energy that comes from breast milk.

Analysis of Variance↗
PubMed1996

Safety, immunogenicity, and protective efficacy of one and three doses of the tetravalent rhesus rotavirus vaccine in infants in Lima, Peru.

An oral rhesus-human rotavirus tetravalent (RRV-TV) vaccine (10(4) pfu of rhesus rotavirus [type G3] and of 3 human-rhesus reassortants [G1, G2, and G4]) was evaluated in a field trial in Lima, Peru. At 2, 3, and 4 months of age, infants received either a dose of RRV-TV, an initial dose of vaccine followed by a dose of placebo at 3 and 4 months, or a dose of placebo. Rotavirus-specific IgA responses were detected by ELISA in 75% of the three-dose vaccine group, 59% of the one-dose vaccine group (P = .05), and 24% of the placebo group (P < .001): 64%, 48%, and 12% of each group, respectively, had a neutralizing antibody response to at least 1 serotype. Both one and three doses of vaccine failed to induce a significant level of protection against rotavirus diarrhea; however, they did provide some protection (range, 35%-66%) against more severe rotavirus diarrhea, especially for episodes caused by type G1.

Animals↗
PubMed1996

Zinc supplementation reduces the incidence of persistent diarrhea and dysentery among low socioeconomic children in India.

Persistent diarrhea (PD) and dysentery (DD) account for most diarrhea-associated deaths among children in developing countries. Zinc deficiency can cause stunting and impaired immune function, both of which are risk factors for these diarrheal illnesses. We investigated the effect of zinc supplementation on the incidence of PD and DD in a community-based, double-blind randomized trial in children 6-35 mo of age. Increase over baseline in plasma zinc concentrations in the supplemented group compared with a control group (3.61 vs. 0.009 mumol.L-1), indicated successful supplementation. The overall reductions in the zinc supplemented group of 21% in the incidence of PD (95% CI -6 to 42%) and 14% in the incidence of dysentery (95% CI -15 to 36%) were not significant. There was a significant interaction of treatment effect with baseline plasma zinc concentration and age for PD and with gender for DD. In the zinc-supplemented group compared with the control group, the incidence of PD was reduced by 73% (P < 0.05; 95% CI 34 to 91%) in children with a baseline zinc < 7.65 mumol.L-1 and by 49% (P < 0.05; 95%CI 24 to 66%) in children > 11 mo of age. Zinc supplementation resulted in a 38% (P < 0.05 95%CI 8 to 59%) reduction in the incidence of DD in boys. There was no effect on PD among children 6-11 mo old or on DD in girls. In conclusion, zinc supplementation had a significant impact on the incidence of persistent diarrhea in children > 1 y old and in children with low plasma zinc, as well as on dysentery in boys. These findings may have important implications for reducing diarrhea-related morbidity and mortality.

Child, Preschool↗
PubMed1996

Validation study of a verbal autopsy method for causes of childhood mortality in Namibia.

Verbal autopsy uses a caretaker interview to determine the cause of death. We conducted a study of the major causes of child death in Namibia to determine the validity of this method. A questionnaire, including signs and symptoms of the diagnoses of interest was administered to the caretaker in 135 deaths of children < 5 years old who were identified from hospital records. The 243 diagnoses included malnutrition (77), diarrhoea (73), pneumonia (36), malaria (33), and measles (24). Sensitivity and specificity of various algorithms of reported signs and symptoms were compared to the medical diagnoses. An algorithm for malnutrition (very thin or swelling) had 73 per cent sensitivity and 76 per cent specificity. An algorithm for cerebral malaria (fever, loss of consciousness or convulsion) had 72 per cent sensitivity and 85 per cent specificity, while for all malaria deaths the same algorithm had low sensitivity (45 per cent) and high specificity (87 per cent). For diarrhoea, loose or liquid stools had high sensitivity (89 per cent), but low specificity (61 per cent). Cough with dyspnoea or tachypnoea had 72 per cent sensitivity and 64 per cent specificity. An algorithm for measles (age > or = 120 days, rash) had 71 per cent sensitivity and 85 per cent specificity. The study results suggest verbal autopsy data can be useful to ascertain the leading causes of death in childhood, but may have limitations for health impact evaluation.

Algorithms↗
PubMed1996

Association between nutritional status, cell-mediated immune status and acute lower respiratory infections in Bangladeshi children.

OBJECTIVE: To investigate the association between nutritional status, cell-mediated immune status and the incidence of acute lower respiratory infections (ALRI). DESIGN: Community-based longitudinal study. SETTING: Three villages in rural Bangladesh at Matlab. SUBJECT: 696 children aged 0-59 months were followed up for a year. METHODS: Trained field workers visited all children every fourth day and collected morbidity data for the preceding three days by recall. To determine the type and severity of respiratory infections, the field workers physically examined each child reporting a cough. Anthropometric status was determined monthly and cell-mediated immune status by skin tests was assessed at the beginning of the study and thereafter every 3 months. RESULTS: The incidence of ALRI was 23 episodes per 100 child-years. A total of 73-78% of the children were below -2 z score weight for age, 15-30% were below - 2 z score weight for height, and 68-76% were below -2 z score height for age. In logistic regression models, malnutrition as assessed by weight-for-height status [odds ratio (OR) 0.66, 95% confidence interval (CI) 0.45-0.96, P = 0.03] or weight-for-age status (OR 0.64, 95% CI 0.45-0.92, P = 0.02) was significant predictor of ALRI. Anergic children had a higher risk of ALRI which approached to be statistically significant (OR 1.81, 95% CI 0.92-3.55, P = 0.08). CONCLUSIONS: Improvement of nutritional and cell-mediated immune status in rural Bangladeshi children should reduce the incidence of ALRI.

Acute Disease↗
PubMed1996

Effect of zinc supplementation on observed activity in low socioeconomic Indian preschool children.

OBJECTIVES: To investigate whether supplementation of zinc in preschool children is associated with improvement in observed activity levels. METHODS: On 2 consecutive days, we performed 5-hour observations with momentary time sampling (instant activity every 10 minutes) in children selected from an ongoing double-blind, randomized trial of zinc supplementation. The study was conducted in Kalkaji, a low-socioeconomic urban population of New Delhi with high diarrheal incidence and rates of malnutrition. A total of 93 children (48 zinc and 45 control) 12 to 23 months of age from an ongoing community-based, randomized, controlled trial received supplements for at least 1 month before study; 71% had received supplementation for more than 120 days. Zinc gluconate (10 mg of elemental zinc) was given daily, with both zinc and control groups receiving vitamins A, B1, B2, B6, D3, and E and niacinamide in addition. RESULTS: Outcomes were percentages of time spent in each of five activity levels and two groups representing high and low movement and overall rating by two activity scores. Children in the zinc group spent 72% more time performing activities in the high-movement group. Among the zinc-supplemented children, the activity rating by the children's activity rating score was 12% higher and by the energy expenditure score was 8.3% higher than in the control group. CONCLUSIONS: In conclusion, zinc supplementation, given along with selected vitamins, was associated with significantly greater activity levels in children. The relationship between the activity increase and locomotor development needs to be investigated, as do the long-term implications of zinc supplementation in terms of developmental status and school performance.

Double-Blind Method↗
PubMed1995

Zinc supplementation in young children with acute diarrhea in India.

BACKGROUND: In developing countries the duration and severity of diarrheal illnesses are greatest among infants and young children with malnutrition and impaired immune status, both factors that may be associated with zinc deficiency. In children with severe zinc deficiency, diarrhea is common and responds quickly to zinc supplementation. METHODS: To evaluate the effects of daily supplementation with 20 mg of elemental zinc on the duration and severity of acute diarrhea, we conducted a double-blind, randomized, controlled trial involving 937 children, 6 to 35 months of age, in New Delhi, India. All the children also received oral rehydration therapy and vitamin supplements. RESULTS: Among the children who received zinc supplementation, there was a 23 percent reduction (95 percent confidence interval, 12 percent to 32 percent) in the risk of continued diarrhea. Estimates of the likelihood of recovery according to the day of zinc supplementation revealed a reduction of 7 percent (95 percent confidence interval, -9 percent to +22 percent) in the risk of continued diarrhea during days 1 through 3 and a reduction of 38 percent (95 percent confidence interval, 27 percent to 48 percent) after day 3. When zinc supplementation was initiated within three days of the onset of diarrhea, there was a 39 percent reduction (95 percent confidence interval, 7 percent to 61 percent) in the proportion of episodes lasting more than seven days. In the zinc-supplementation group there was a decrease of 39 percent (95 percent confidence interval, 6 percent to 70 percent) in the mean number of watery stools per day (P = 0.02) and a decrease of 21 percent (95 percent confidence interval, 10 percent to 31 percent) in the number of days with watery diarrhea. The reductions in the duration and severity of diarrhea were greater in children with stunted growth than in those with normal growth. CONCLUSION: For infants and young children with acute diarrhea, zinc supplementation results in clinically important reductions in the duration and severity of diarrhea.

Acute Disease↗
PubMed1995

Rectal irrigations for the prevention of postoperative enterocolitis in Hirschsprung's disease.

The purpose of this clinical trial was to examine the role of rectal irrigations in the prevention of postoperative enterocolitis in children with Hirschsprung's disease. Over the past 22 years 177 children had surgical treatment for Hirschsprung's disease at a single pediatric hospital. Five children have died of other causes. Of the remaining 172 patients, follow-up clinical information was obtained from 135 (78%). In 1989, all of the children undergoing surgical reconstruction for Hirschsprung's disease were placed on routine postoperative rectal irrigations with normal saline. The parents were instructed in the irrigation technique before leaving the hospital. Irrigations were started 1 to 2 weeks postoperatively and were performed two times a day for 3 months, then once a day for an additional 3 months. There were no complications from the irrigations themselves. A previous report from the authors' institution has documented five sudden deaths over the past 22 years from fulminant postoperative enterocolitis. These five children all had an unremarkable postoperative recovery, then developed a rapidly progressive diarrheal illness. All of these deaths occurred before the institution of routine postoperative irrigations. Of the 135 patients in this review, 40 had the postoperative rectal irrigations. The remaining 95 children serve as historical controls. Data analysis showed that 34 of the 95 children in the nonirrigation cohort developed postoperative enterocolitis compared with 3 of 40 in the rectal irrigation cohort; P < .001 using Fisher's exact test. In the authors' experience, routine postoperative rectal irrigations have significantly decreased the incidence and severity of enterocolitis in children after surgical correction of Hirschsprung's disease.

Child↗
PubMed1995

Gastrointestinal function after surgical correction of Hirschsprung's disease: long-term follow-up in 135 patients.

This study is a retrospective review of all children treated for Hirschsprung's disease over the past 22 years at a single pediatric institution. During this time 177 patients had definitive surgical reconstruction. Five children died of causes unrelated to Hirschsprung's disease, and five children died from enterocolitis after an uneventful postoperative course. Clinical follow-up information was obtained from 135 (78%). Demographic data includes the following: sex ratio 74% male, 26% female; current mean age 9.9 years; mean length of follow-up 7.9 years (range, 3 months to 21.5 years). Mean age at surgical reconstruction was 1.6 years. Definitive surgical procedures included endorectal pull-through (Soave), 21%; modified Duhamel, 67%; extended side-to-side ileocolic anastomosis, 8%; rectal myomectomy, 4%. Transition zone was within rectum or rectosigmoid region in 86%. Overall, 32% (43/135) report difficulty with fecal soiling, and 12.6% (17/135) identify this as a severe problem. These numbers include patients with trisomy 21 and total colonic aganglionosis. Severe fecal soiling was reported in 7.1% (2/28) after an endorectal pull-through, and in 12.1% (11/91) after the modified Duhamel. The difference in incidence of soiling after these two procedures is not statistically significant. However, 40% (4/10) of the patients after the long side-to-side anastomosis for total colonic aganglionosis report severe problems with fecal soiling (P = .03). Surgical reconstruction for Hirschsprung's disease provides near-normal gastrointestinal function for the majority of children, but long-term follow-up shows significant residual problems with soiling in 12.6% of the patients. This is consistent with reported experience worldwide.

Adolescent↗
PubMed1995

Validity and epidemiology of reported poor appetite among Peruvian infants from a low-income, periurban community.

To assess the validity of maternal reports of poor infant appetite, these histories were compared with measured energy consumption on 1621 d of observation of 131 Peruvian infants in a low-income community. Mean (+/- SD) total energy intakes on days with reported anorexia were 338 +/- 88 kJ/kg body wt in infants 1-6 mo of age and 299 +/- 92 kJ/kg body wt in infants aged > 6 mo compared with 395 +/- 92 and 342 +/- 88 kJ/kg body wt in the respective age groups when appetites were reportedly normal (P < 0.001). Energy intake from non-breast-milk sources was more affected than energy from breast milk. The epidemiology of poor appetite was assessed in 153 infants who were monitored longitudinally during their first year of life. The prevalence of reported anorexia increased progressively from 22 to 317/1000 d of observation from < 1 to 11 mo of age. Infant age and the presence of fever, diarrhea, and respiratory illnesses were each associated negatively with the presence of reduced appetite. Poor appetite, rather than lack of food, may explain in part the low energy intakes by infants in this community.

Anorexia↗
PubMed1995

Maternal reporting of acute respiratory infection in Egypt.

BACKGROUND: Acute respiratory infection (ARI) is a major cause of childhood morbidity and mortality in developing countries. Community surveys are used to determine the proportion of children with ARI for whom care is sought by questioning mothers about the signs and symptoms of illness episodes. The validity of this approach has been studied infrequently. METHODS: We evaluated maternal reporting of signs and symptoms 2 and 4 weeks after diagnosis among 271 Egyptian children < 5 years old. Children with ARI were evaluated by physical examination, chest radiography, and pulse oximetry, and were alternately assigned for a maternal interview about the episode 14 or 28 days later. RESULTS: For radiographically-defined acute lower respiratory infection (ALRI), the sensitivity of several symptoms for combined open- and close-ended questions was relatively high: nahagan (deep or rapid breathing) (80%), nafas sarie (fast breathing) (66%), and kharfasha (coarse breath sounds) (63%). The specificity of these terms was 50-68%. The specificity was inversely related to the follow-up time. No term provided both a sensitivity and specificity of > 50% at day 28 across the radiographically, clinically- and pulse oximetry-based definitions of ALRI. Spontaneously mentioned karshet nafas (difficult or rapid breathing) at 14 days had a specificity and sensitivity for radiographic ALRI of 87% and 41%, respectively, suggesting that this term is a good choice for community surveys. CONCLUSIONS: Maternal reporting of ARI symptoms is non-specific 2 and 4 weeks after diagnosis but may be useful for monitoring trends in the proportion of children with pneumonia who receive medical care. To maximize specificity, ARI programmes should generally use a recall period of 2 weeks.

Acute Disease↗
PubMed1995

Potential for misclassification of infants' usual feeding practices using 24-hour dietary assessment methods.

Feeding patterns of 131 low income Peruvian infants were assessed by 1574 single-day studies (12-h observations plus 12-h recall) of dietary intake and by mothers' monthly reports of usual feeding practices to determine whether feeding pattern classification depends on the assessment method used. Results suggest that single-day studies produce a different view of feeding practices than do mothers' reports of usual behavior. Exclusive breast-feeding in infants younger than 4 mo was observed 25% more often than reported. Non-human milk consumption was reported 30% more often than observed. Disagreement between reported and observed practices was related by logistic regression analyses to mother's age and education, number of children younger than 5 y in the home and infant age and illness on the observation day. Most disagreement between reported and observed behavior could have been due to daily variation in feeding practices. Consumption during the past 24 h should not be used alone as the basis for classifying infant feeding practices in survey research.

Adolescent↗
PubMed1995

Priority setting in case management based on need and risk.

The Long-Term Care Program of the Capital Regional District, Victoria, British Columbia, experienced increasing demands for service and corresponding pressures on community case managers. A priority setting tool was developed and implemented as a means of prioritizing new intakes. This tool represents a shift toward a broader scope of practice in which both client need and risk are measured. Priorities based on these scores have streamlined current case management practice and helped to ensure that newly referred individuals are seen in a consistent and timely manner.

Case Management↗