Prevalence and aetiology of congenital birth defects, infant mortality and mental retardation in Lahore, Pakistan: a prospective cohort study

AIM: To study the health and development of children in a developing and low-income country. METHODS: The health and development of children in Lahore in northern Pakistan have been studied since 1981 in a collaborative project between Pakistani and Swedish university institutions and the Swedish Agency for Research Cooperation with Developing Countries (SAREC). The study described in this paper comprised four different areas in Lahore with different degrees of urbanization and different social conditions. All pregnancies in the four areas were registered during the period March 1984 to July 1986 and were followed up from the 5th month of pregnancy. All 1476 children born after 1 September 1984 were followed up from birth to 12 y of age. RESULTS: The perinatal mortality in the whole material was 5.4%. It was highest in the periurban slum (7.5%) and lowest in the upper-middle class cohort (3.3%). Overall infant mortality was 10%. It was highest (14%) in the periurban slum and lowest (2%) in the upper-middle class group. Overall incidence of serious birth defects was 5%. It was highest in the periurban slum community (7%) and lowest in the upper-middle class cohort (3%). The overall cumulative incidence of severe mental retardation per 100 live births was 1.1. It was highest (2.2) in the periurban slum and lowest (0.4) in the upper-middle class group. The overall prevalence of mild mental retardation among 6-10-y-old children was 6.2 per 100. It was highest in the periurban slum (10.5) and lowest (1.3 per 100) in the upper-middle class group. Poverty, malnutrition, birth trauma and consanguinity were common causes of infant mortality and mental retardation in Lahore, Pakistan. CONCLUSION: Preventive measures with provision of obstetric and health services, services for genetic information and risk evaluation, vaccination programmes and identification of children with retarded development for specific stimulation and habilitation measures, e.g. organized play activities, are important in developing and low-income countries.     

Risk for birth defects among premature infants: a population-based study

OBJECTIVE: To investigate the relationship between prematurity and birth defects. STUDY DESIGN: In a population-based cohort study, infants with birth defects were ascertained through the Metropolitan Atlanta Congenital Defects Program, a surveillance system with active methods of ascertainment. Gestational age data were obtained from birth certificates of liveborn, singleton infants with and without birth defects born in the 5-county metropolitan Atlanta area. RESULTS: Among 264,392 infants with known gestational ages born between 1989 and 1995, 7738 were identified as having birth defects (2.93%). Premature infants (<37 weeks' gestation) were more than two times as likely to have birth defects than term infants (37-41 weeks) (risk ratio = 2.43; 95% CI 2.30-2.56). This relationship was evident for several categories of birth defects. The rate of birth defects varied by gestational age categories, with the highest risk in the 29- to 32-week gestational age category (risk ratio = 3.37). CONCLUSIONS: The risk for birth defects is increased in premature infants. Awareness of this relationship is important for clinicians caring for premature infants. The morbidity and mortality associated with a particular defect may be significantly altered by the presence of prematurity. Further study of this association may provide insight into the etiology of these relatively common problems.     

Hospitalisations from birth to 5 years in a population cohort of Western Australian children with intellectual disability

Aims: To describe the hospitalisation history in the first five years of life for all children born in Western Australia (WA) between 1983 and 1992 and diagnosed with intellectual disability (ID). Methods: Unit record linkage of the WA Midwives Collection, WA Intellectual Disability Database, and the WA Hospital Morbidity Dataset provided the population database of WA born children with and without ID. Affected children were divided into those co-affected with autism spectrum disorders (ASD), and those whose ID had or had no known biomedical cause. Those without a biomedical cause were further subdivided into mild–moderate and severe categories. Results: On average, ID affected children were more likely than non-affected children to be admitted to hospital (RR: 1.64; 95% CI 1.6 to 1.7), on more occasions (5.3 versus 2.2 admissions), for longer (29.6 versus 8.3 days), and for a larger range of clinical diagnoses. The only exception was the group of children co-diagnosed with ASD whose hospitalisation profile resembled more that of non-affected children. Conclusions: This total population study is unique because of the availability of the system of linkable population registers and administrative health databases in WA. The results indicated that this vulnerable population of children with ID has substantial medical needs. This paper points to the need for authorities to develop supportive programmes for this population especially in the current climate of de-medicalisation of ID. More research is not only needed on the welfare of the affected children but also on the impact of the substantial medical and other needs of affected children on the rest of their immediate and extended families.     

The relationship between birth weight and childhood asthma: a population-based cohort study

BACKGROUND: Because obesity promotes inflammation and imposes mechanical constraints to the airways, a high birth weight may be a risk factor for asthma in childhood. However, to our knowledge, few studies have examined this potential relationship. OBJECTIVE: To determine the relationship between high birth weight and risk of emergency visits for asthma during childhood. DESIGN: Population-based cohort study. SETTING: Alberta, Canada. PARTICIPANTS: All neonates born at term (> or =37 weeks) between April 1, 1985, and March 31, 1988, in Alberta (N = 83,595). We divided the cohort into birth-weight categories: low (<2.5 kg), normal (2.5-4.5 kg), or high (>4.5 kg). The cohort was observed prospectively for 10 years.Main Outcome Measure Comparison of risk of emergency visits for asthma over 10 years across the birth-weight categories. RESULTS: Neonates born with a high birth weight had a significantly increased risk of emergency visits for asthma during childhood compared with neonates born with a normal birth weight (relative risk [RR], 1.16; 95% confidence interval [CI], 1.04-1.29). The relationship between birth weight and emergency visits for asthma beyond a birth weight of 4.5 kg was linear, such that every increment of 0.10 kg in birth weight was associated with an additional 10% (95% CI, 2%-19%) increase in the risk of emergency visits for asthma. Other factors associated with an elevated risk for emergency asthma visits during childhood included male sex (RR, 1.26; 95% CI, 1.22-1.30), aboriginal status (RR, 1.20; 95% CI, 1.11-1.29), and low-income status (RR, 1.11; 95% CI, 1.06-1.16). CONCLUSIONS: A high, but not low, birth weight is a risk factor for increased emergency visits during childhood. The risk increases linearly beyond a birth weight of 4.5 kg.     

Neuropsychological performance in low birth weight preschoolers: a population-based, controlled study

The aim was to evaluate neuropsychological performance and its pre-, and perinatal predictors in low birth weight (LBW) preschool children. A population-based sample of 137 5-year-old children with birth weights less than 2000 g and without major handicaps was compared with a random sample of 152 normal birth weight term controls. Main assessment tools were all subscales from the Wechsler Preschool and Primary Scale of Intelligence Revised, subscales from the Illinois Test of Psycholinguistic Abilities and tests of manual dexterity and figure copying. The LBW children showed significantly lower mean scores compared to controls on tests of visuo-spatial and visuo-motor abilities, but were comparable to controls in other areas, confounding parental factors were controlled for. 14 of the LBW children, there were signs of maternal chorio-amnionitis. Twelve of these had premature rupture of membranes lasting more than 24 h. These 14 children had a mean performance IQ of 87 (SD 5) compared to 100 (SD 15) for the LBW children without maternal signs of chorio-amnionitis (P = 0.001). Having a small head circumference at birth was a less powerful, but statistically significant predictor of impaired performance. Conclusion Low birth weight is associated with impaired performance on visuo-spatial and visuo-motor tasks. Signs of maternal chorio-amnionitis and a small head circumference at birth may be risk factors for such impairment. Received: 20 November 1996 / Accepted: 5 May 1997     

Hospitalisations from birth to 5 years in a population cohort of Western Australian children with intellectual disability.

AIMS: To describe the hospitalisation history in the first five years of life for all children born in Western Australia (WA) between 1983 and 1992 and diagnosed with intellectual disability (ID). METHODS: Unit record linkage of the WA Midwives Collection, WA Intellectual Disability Database, and the WA Hospital Morbidity Dataset provided the population database of WA born children with and without ID. Affected children were divided into those co-affected with autism spectrum disorders (ASD), and those whose ID had or had no known biomedical cause. Those without a biomedical cause were further subdivided into mild-moderate and severe categories. RESULTS: On average, ID affected children were more likely than non-affected children to be admitted to hospital (RR: 1.64; 95% CI 1.6 to 1.7), on more occasions (5.3 versus 2.2 admissions), for longer (29.6 versus 8.3 days), and for a larger range of clinical diagnoses. The only exception was the group of children co-diagnosed with ASD whose hospitalisation profile resembled more that of non-affected children. CONCLUSIONS: This total population study is unique because of the availability of the system of linkable population registers and administrative health databases in WA. The results indicated that this vulnerable population of children with ID has substantial medical needs. This paper points to the need for authorities to develop supportive programmes for this population especially in the current climate of de-medicalisation of ID. More research is not only needed on the welfare of the affected children but also on the impact of the substantial medical and other needs of affected children on the rest of their immediate and extended families.     

Diabetes mellitus during pregnancy and the risks for specific birth defects: a population-based case-control study

Although the excess risk for birth defects among children of mothers with diabetes mellitus is well documented, there are few data concerning the risk for specific malformations. In the Atlanta Birth Defects Case-Control Study, those risks for malformations were evaluated. The population-based study included 4929 live and stillborn babies with major malformations ascertained by the Metropolitan Atlanta Congenital Defects Program in the first year of life born to residents of Metropolitan Atlanta between 1968 and 1980. The study also included 3029 nonmalformed live babies who were frequency-matched to case babies by race, period of birth, and hospital of birth. The relative risk for major malformations among infants of mothers with insulin-dependent diabetes mellitus (n = 28) was 7.9 (95% confidence interval [CI]1.9, 33.5) compared with infants of nondiabetic mothers. The relative risks for major central nervous system and cardiovascular system defects were 15.5 (95% CI = 3.3, 73.8) and 18.0 (95% CI = 3.9, 82.5), respectively. The absolute risks for major, central nervous system, and cardiovascular system malformations among infants of diabetic mothers were 18.4, 5.3, and 8.5 per 100 live births, respectively. Infants of mothers with gestational diabetes mellitus who required insulin during the third trimester of pregnancy were 20.6 (95% CI = 2.5, 168.5) times more likely to have major cardiovascular system defects than infants of nondiabetic mothers. The absolute risk for infants of this group of diabetic mothers was 9.7%. No statistically significant differences were found among infants of mothers with gestational diabetes mellitus who did not require insulin during pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)     

A retrospective population-based study of childhood hospital admissions with record linkage to a birth defects registry

Background  

Using population-based linked records of births, deaths, birth defects and hospital admissions for children born 1980–1999 enables profiles of hospital morbidity to be created for each child.