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Biomedical subjects

F E Onyango

Publications and source records attributed to F E Onyango.

At least 19 recordsLinked to original sources
PubMed2001

Effect of breastfeeding on mortality among HIV-1 infected women: a randomised trial.

BACKGROUND: We have completed a randomised clinical trial of breastfeeding and formula feeding to identify the frequency of breastmilk transmission of HIV-1 to infants. However, we also analysed data from this trial to examine the effect of breastfeeding on maternal death rates during 2 years after delivery. We report our findings from this secondary analysis. METHODS: Pregnant women attending four Nairobi city council clinics were offered HIVtests. At about 32 weeks' gestation, 425 HIV-1 seropositive women were randomly allocated to either breastfeed or formula feed their infants. After delivery, mother-infant pairs were followed up monthly during the first year and quarterly during the second year until death, or 2 years after delivery, or end of study. FINDINGS: Mortality among mothers was higher in the breastfeeding group than in the formula group (18 vs 6 deaths, log rank test, p=0.009). The cumulative probability of maternal death at 24 months after delivery was 10.5% in the breastfeeding group and 3.8% in the formula group (p=0.02). The relative risk of death for breastfeeding mothers versus formula feeding mothers was 3.2 (95% CI 1.3-8.1, p=0.01). The attributable risk of maternal death due to breastfeeding was 69%. There was an association between maternal death and subsequent infant death, even after infant HIV-1 infection status was controlled for (relative risk 7.9, 95% CI 3.3-18.6, p<0.001). INTERPRETATION: Our findings suggest that breastfeeding by HIV-1 infected women might result in adverse outcomes for both mother and infant.

Adult↗
PubMed2000

Effect of breastfeeding and formula feeding on transmission of HIV-1: a randomized clinical trial.

CONTEXT: Transmission of human immunodeficiency virus type 1 (HIV-1) is known to occur through breastfeeding, but the magnitude of risk has not been precisely defined. Whether breast milk HIV-1 transmission risk exceeds the potential risk of formula-associated diarrheal mortality in developing countries is unknown. OBJECTIVES: To determine the frequency of breast milk transmission of HIV-1 and to compare mortality rates and HIV-1-free survival in breastfed and formula-fed infants. DESIGN AND SETTING: Randomized clinical trial conducted from November 1992 to July 1998 in antenatal clinics in Nairobi, Kenya, with a median follow-up period of 24 months. PARTICIPANTS: Of 425 HIV-1-seropositive, antiretroviral-naive pregnant women enrolled, 401 mother-infant pairs were included in the analysis of trial end points. INTERVENTIONS: Mother-infant pairs were randomized to breastfeeding (n = 212) vs formula feeding arms (n = 213). MAIN OUTCOME MEASURES: Infant HIV-1 infection and death during the first 2 years of life, compared between the 2 intervention groups. RESULTS: Compliance with the assigned feeding modality was 96% in the breastfeeding arm and 70% in the formula arm (P<.001). Median duration of breastfeeding was 17 months. Of the 401 infants included in the analysis, 94% were followed up to HIV-1 infection or mortality end points: 83% for the HIV-1 infection end point and 93% to the mortality end point. The cumulative probability of HIV-1 infection at 24 months was 36.7% (95% confidence interval [CI], 29.4%-44.0%) in the breastfeeding arm and 20.5% (95% CI, 14.0%-27.0%) in the formula arm (P = .001). The estimated rate of breast milk transmission was 16.2% (95% CI, 6.5%-25.9%). Forty-four percent of HIV-1 infection in the breastfeeding arm was attributable to breast milk. Most breast milk transmission occurred early, with 75% of the risk difference between the 2 arms occurring by 6 months, although transmission continued throughout the duration of exposure. The 2-year mortality rates in both arms were similar (breastfeeding arm, 24.4% [95% CI, 18.2%-30.7%] vs formula feeding arm, 20.0% [95% CI, 14.4%-25.6%]; P = .30). The rate of HIV-1-free survival at 2 years was significantly lower in the breastfeeding arm than in the formula feeding arm (58.0% vs 70.0%, respectively; P = .02). CONCLUSIONS: The frequency of breast milk transmission of HIV-1 was 16.2% in this randomized clinical trial, and the majority of infections occurred early during breastfeeding. The use of breast milk substitutes prevented 44% of infant infections and was associated with significantly improved HIV-1-free survival.

AIDS Serodiagnosis↗
PubMed1999

Effects of passive smoking and breastfeeding on childhood bronchial asthma.

OBJECTIVE: To evaluate the effect of passive smoking and breastfeeding on the severity and age of onset of bronchial asthma. DESIGN: Cross-sectional study. SETTING: Paediatric observation ward and paediatric chest clinic, Kenyatta National Hospital. PATIENTS: Children aged between one and 120 months. RESULTS: More than fifty per cent of the children had their first wheeze at less than 12 months of age and 68% were categorised as having moderate to severe asthma. Passive smoking was positively significantly associated with early onset of wheezing (chi 2 = 6.22, p = 0.012, Odds ratio = 2.44, 95% CI 1.2,5.0), and also, at a non significant level, to severity of asthma (chi 2 = 2.8, p = 0.09, Odds ratio = 2.1, 95% CI 0.9,4.7). On the other hand, exclusive breastfeeding was significantly negatively associated with severity of bronchial asthma (chi 2 = 4.02, p = 0.045, Odds ratio = 0.4, 95% CI 0.14,0.98), but did not seen to have effect on age of onset of the disease (chi 2 = 0.0006, p = 0.94, Odds ratio = 0.9, 95% CI 0.4,2.2). CONCLUSION: Passive smoking is associated with early onset of asthma and possibly with development of severe asthma while exclusive breastfeeding is protective against development of severe asthma but does not seem to affect the age of onset of this disease.

Age of Onset↗
PubMed1998

X-ray diagnosable pneumonia in children with severe malnutrition at Kenyatta National Hospital.

OBJECTIVES: To estimate the prevalence of radiologically evident pneumonia among children with severe malnutrition and to evaluate the diagnostic utility of commonly used clinical indicators of pneumonia among children with severe malnutrition. METHODS: All children with severe malnutrition and admitted at the then Paediatric Observation Ward without congestive cardiac failure, severe anaemia, or severe dehydration, were clinically evaluated and a posteroanterior chest X-ray taken for each child. Pneumonia was diagnosed on the basis of radiological changes consistent with pneumonia as reported by an experienced radiologist. The performance of the various clinical parameters as diagnostic tests for pneumonia were also evaluated. SETTING: Kenyatta National Hospital, a tertiary level teaching institution for the University of Nairobi. RESULTS: One hundred and seven children comprising 68 males and 39 females were recruited into the study. Of these children, 38 had kwashiorkor, 40 had marasmus, while 29 had marasmic kwashiorkor. Radiological evidence of pneumonia was found in 58% of children with kwashiorkor, 75% with marasmic kwashiorkor, and 82% with marasmus. All the commonly used clinical parameters performed poorly as diagnostic tests for pneumonia among children with severe malnutrition. CONCLUSION: Prevalence of pneumonia was very high among children with severe malnutrition. Available clinical parameters, singly or in combination, are poor diagnostic tools for pneumonia in children with severe malnutrition. It is advisable to treat children with severe malnutrition as if they had pneumonia, even in the absence of suggestive clinical signs.

Age Distribution↗
PubMed1995

Efficacy of halofantrine in the treatment of uncomplicated falciparum malaria.

In the last decade, Plasmodium falciparum resistance to a number of commonly used anti-malarials especially chloroquine, has increased considerably. Newer anti-malarial drugs are therefore being aggressively evaluated as alternatives. A randomized double-blind controlled trial was therefore undertaken, to compare the efficacy of halofantrine to that of metakelfin, in the treatment of moderately severe infections of Plasmodium falciparum in an endemic malaria area in Kenya. Three hundred and thirty five subjects with laboratory confirmed malaria were recruited and randomized to receive treatment with either halofantrine (171 subjects) or metakelfin (164 subjects). Two thirds (66%) of the study subjects were under the age of five years, and were therefore considered to have minimal immunity. All study subjects were initially admitted to hospital for three days and then followed up as out-patients on days 7, 14, 21, and 28. The level of parasitaemia, the presence of fever and the occurrence of adverse effects were evaluated. Halofantrine was found to be comparable to metakelfin in terms of resolution of fever (mean time 45 and 51 hours respectively). No major adverse side effects were observed. Halofantrine is a viable drug in the treatment of uncomplicated P. falciparum malaria.

Adolescent↗
PubMed1995

Prevalence of persistent diarrhoea in children aged 3-36 months at the Kenyatta National Hospital, Nairobi, Kenya.

Three hundred and eighty four children aged 3-36 months admitted to the Infectious Diseases Hospital (IDH) with diarrhoea were studied for persistent diarrhoea (PD), defined as diarrhoea lasting more than 14 days. To establish the duration of diarrhoea, the children were evaluated daily while in hospital and on days seven, fourteen, twenty one and twenty eight of the diarrhoea episode, if discharged. Of these children, 268 (69.8%) were less than 12 months. There was a slight male preponderance with a male to female ratio of 1.2:1. Twenty (5.4%) children presented with diarrhoea of more than 14 days at admission while of the 364 who presented with diarrhoea of less than 14 days at admission, 40 (11%) developed persistent diarrhoea, giving a total PD rate of 16.5%. The peak age for PD was nine months with no sex difference. Some possible risk factors for PD were identified as blood in stools, pneumonia, malnutrition, not breastfeeding, severe dehydration and antibiotic treatment. The total number of deaths in the study cases was 50, giving a case fatality rate of 13.6%. Of the children with PD, 19(31.7%) died. The children with PD were at a four times greater risk of dying (P<0.001, OR = 4.16). This study indicates that prevalence of PD among children admitted to IDH is high; and carries a high case fatality.

Child, Preschool↗
PubMed1994

Characteristics related to the incidence and prevalence of acute respiratory tract infection in young children in Kenya.

Acute respiratory tract infection (ARI) in children is a prevalent condition that results in substantial morbidity and consumes large portions of health care resources in developing countries. We examined factors associated with the reported incidence and prevalence of ARI in a 3-year longitudinal study of 485 children < 5 years of age in rural Kenya. A large number of environmental factors, household and family characteristics, and child-specific factors were examined with use of multivariable methods. Few variables that may play a role in the incidence and prevalence of ARI (e.g., household tobacco use and weight z-score) were found to be related to such rates. Several factors related to ARI incidence and prevalence (e.g., mother's age, number of children, and community) were found to be associated with only mild ARI episodes. Evidence is presented to support the hypothesis that these factors are related to differential reporting of mild ARI episodes. The impact of such differential reporting on health care utilization and health education is discussed.

Child, Preschool↗
PubMed1993

Hypoxaemia in young Kenyan children with acute lower respiratory infection.

OBJECTIVES: To determine the prevalence, clinical correlates, and outcome of hypoxaemia in acutely ill children with respiratory symptoms. DESIGN: Prospective observational study. SETTING: Paediatric casualty ward of a referral hospital at 1670 m altitude in Nairobi, Kenya. SUBJECTS: 256 Infants and children under 3 years of age with symptoms of respiratory infection. MAIN OUTCOME MEASURES: Prevalence of hypoxaemia, defined as arterial oxygen saturation < 90% determined by pulse oximetry, and condition of patient on the fifth day after admission. RESULTS: Over half (151) of the children were hypoxaemic, and short term mortality was 4.3 times greater in these children. In contrast, the relative risk of a fatal outcome in children with radiographic pneumonia was only 1.03 times that of children without radiographic pneumonia. A logistic regression model showed that in 3-11 month old infants a respiratory rate > or = 70/min, grunting, and retractions were the best independent clinical signs for the prediction of hypoxaemia. In the older children a respiratory rate of > or = 60/min was the single best clinical predictor of hypoxaemia. The presence of hypoxaemia predicted radiographic pneumonia with a sensitivity of 71% and specificity of 55%. CONCLUSIONS: Over half the children presenting to this referral hospital with respiratory symptoms were hypoxaemic. A group of specific clinical signs seem useful in predicting hypoxaemia. The clear association of hypoxaemia with mortality suggests that the detection and effective treatment of hypoxaemia are important aspects of the clinical management of acute infections of the lower respiratory tract in children in hospital in developing regions.

Acute Disease↗
PubMed1993

Recognition of illness in very young infants by inexperienced health workers.

To determine whether inexperienced health workers can recognize severe infection in infants less than 3 months of age, a study was conducted of 200 infants with cough, fever or 'not feeling well'. The presence or absence of five symptoms: cough, difficulty in breathing, feeding problem, fever or history of convulsions, and ten signs: appearing ill, respiratory rate > or = 60/min, chest indrawing, grunting, cyanosis, wheeze, lethargy, 'too hot', 'too cold' or abdominal distension, were recorded by a health worker, who made a diagnosis of 'ill' or 'mildly ill'. Each infant was then reviewed by an experienced paediatrician who made a diagnosis of 'ill' (pneumonia, sepsis, meningitis or other severe illness) or 'mildly ill'. Using these diagnoses as the 'gold standard', the sensitivity, specificity, and positive predictive values of each parameter were calculated. In 89% of the 200 infants, the health worker made the correct diagnosis. Forty infants were admitted. In 36 instances (90%) the health worker made the correct decision. The most discriminating symptoms and signs were 'not feeding well', 'appears ill', chest indrawing and grunting. A respiratory rate > or = 60/min was 78% sensitive and 69% specific. Our study suggests that inexperienced health workers can recognize severe illness in infants under 3 months of age.

Health Personnel↗
PubMed1993

Effect of vitamin A on diarrhoeal and respiratory complications of measles.

A randomized placebo-controlled trial of high dose vitamin A in acute measles was performed in Nairobi, Kenya to determine if it reduced the incidence or severity of diarrhoeal and respiratory complications. On enrollment laryngotracheobronchitis (LTB) pneumonia, diarrhoea and otitis media were each found in 45-80% of children in the treatment and placebo groups. While 4 of 119 cases of LTB in the placebo group progressed to grade III (loud stridor, markedly diminished air entry, chest indrawing, cyanosis), none of 116 in the vitamin A group did. Episodes of diarrhoea, but not pneumonia, resolved faster and were less severe in the vitamin A group. There were no differences in the incidences of pneumonia, LTB or diarrhoea during hospitalization, but children treated with vitamin A had a lower rate of developing otitis media. The overall case fatality rate was 2.7% and did not differ by group. These findings, along with those from three other trials in Africa, suggest that high dose vitamin A reduces the severity of complications during measles.

Acute Disease↗
PubMed1990

Mortality patterns in a rural Kenyan community.

Causes of death of 239 children below the age of 5 years in a rural community were determined using structured questionnaires. It was found that mortality was highest in infancy, accounting for 63% of all deaths with a trend of decreasing mortality with increasing age. The commonest cause of death was ARI (pneumonia and measles) accounting for 49% of the deaths, followed by diarrhoeal illnesses (8.8%). Only half of the deaths (51.5%) occurred at some health facility, though 77% of all children had been taken to a health facility for treatment during the fatal illness.

Age Factors↗
PubMed1990

Childhood asthma at Kenyatta National Hospital, Nairobi.

Between January 1986 and July 1988, 356 children with bronchial asthma below 14 years of age were evaluated at the Kenyatta National Hospital. 21.3% experienced initial asthmatic attacks before the age of six months and 55.1% before 2 years. Only 8% of the study patients were below the age of 2 years at recruitment. The male:female ratio was 1:1. Physical exercise led to precipitation or worsening of attacks in 43.4% while 71.6% of the patients experienced attacks in the evening or at night. 18.5% and 42.9% had personal history of atopic dermatitis and allergic rhinitis respectively. The study shows that a substantial number of patients experience initial asthmatic attacks before the age of 6 months contrary to what has been previously believed.

Adolescent↗
PubMed1990

Verbal autopsy: a tool for determining cause of death in a community.

Verbal autopsy was used to determine causes of death in 239 children under the age of 5 years. The diagnosis derived from verbal autopsy was corroborated with hospital diagnosis in 39 cases. There was concurrence of diagnosis in 72% of the cases. Using the diagnosis of bronchopneumonia to validate the method, verbal autopsy was found to have a sensitivity of 71%, specificity of 92%, a positive predictive value of 85%. Reliability index of agreement was 0.654. Recall period up to 29 months after death was found to be reliable.

Bias↗
PubMed1990

Indoor air pollution in a Kenyan village.

In April 1986, a study was carried out within rural households in Maragua area, Muranga District, Republic of Kenya, to assess the degree of indoor air pollution and to find its relationship, if any, to acute respiratory infections (ARI) among children aged below 5 years within the study. This study was carried out within an ongoing aetiological and epidemiological community study on ARI as a collaborative effort between the Department of Paediatrics, University of Nairobi; the Department of Chemistry, Kenyatta University; the Department of Environmental Sciences, Agricultural University, Wagenigen, The Netherlands; the World Health Organization; and the Ministry of Health, Republic of Kenya. Repeated 24 hour measurements of respirable suspended particles (RSP) and nitrogen dioxide (NO2), were carried out in 36 randomly selected houses where most of the cooking was done on open fires using firewood and crop residues as fuel. Data on house characteristics and activity in the study were gathered by questionnaire. The mean of 24 hour average RSP concentration (1400mg/m3), average during the 7 hours of daily burning (3000-4000mg/m3), and evening peak levels (up to 3600mg/m3) indicate that deleterious health effects due to exposure to excessive levels of toxic pollutants in smoke from biomass combustion are likely to occur especially among pre-school children and women. Concentrations of selected polycyclic hydrocarbons in the particulate material were found to be high. It was not possible to demonstrate a relationship between the indoor air pollution and episodes of ARI partly because of small sample size and also the more or less homogeneous nature of pollution among all the households.

Air Pollutants↗
PubMed1989

The diagnostic value of various features for acute lower respiratory infection among under fives.

One hundred and fifty children aged between 5 months and 5 years with cough of less than 2 weeks duration, and presenting at the paediatric filter clinic and paediatric observation ward of the Kenyatta National Hospital between July and December 1985 were each evaluated by a complete history, physical examination, and a chest X-ray. Ninety of them (or 60%) had radiological evidence of pneumonia. Respiratory rate of over 50 per minute, chest indrawing, flaring of alae nasae, and a history of rapid breathing were found to be valuable indicators of pneumonia.

Child, Preschool↗
PubMed1989

Bacteriology of unheated expressed breast milk stored at room temperature.

Thirty samples of unheated expressed breast milk (EBM) from thirty lactating mothers, stored at room temperature (RT) and in the refrigerator (at +4 degrees C), were examined for the degree of bacterial contamination at two hourly intervals upto eight hours. All the EBM samples contained bacteria, mostly of normal skin flora; Staphylococcus albus 76.7%; Streptococcus viridans 40%. Potential pathogens were isolated in small numbers: Escherichia coli 26%, Streptococcus faecalis 13.6% and Staphylococcus aureus 6.7%. The bacterial colony counts (BCC) were consistently low; Mean initially 5.438 x 10(3) cfu/mm3 with a range of 0.15-23.1 x 10(3) cfu/mm3 and showed a significant reduction on storage in both EBM samples stored at RT and at +4 degrees C. The study proved that it is safe for mothers to keep unheated EBM at RT for at least eight hours before bacteria can multiply beyond unacceptable levels.

Female↗