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Biomedical subjects

P O Pharoah

Publications and source records attributed to P O Pharoah.

At least 19 recordsLinked to original sources
PubMed2003

The epidemiology of sudden infant death syndrome.

BACKGROUND: Twins compared to singletons are at increased risk of sudden infant death syndrome (SIDS). AIMS: To compare the epidemiology of SIDS in twins and singletons and to test the hypothesis that monozygous (MZ) were at greater risk of SIDS than dizygous (DZ) twins. METHODS: Data from the Office for National Statistics on all registered live births and infant deaths with registered cause of death "sudden unexpected death in infancy" in England and Wales from 1993 to 1998 were obtained, together with the registered birth weight and, for twins, whether they were of like or unlike sex. RESULTS: The crude relative risk of SIDS in twins is twice that in singletons. There has been a significant temporal decline in SIDS mortality. There is also a significant increase in risk with decreasing birth weight for both twins and singletons. The birth weight specific risk of SIDS in all except for those > or =3000 g is greater in singletons than in twins. There is no significant difference in risk of SIDS in like compared with unlike sex twins. CONCLUSIONS: In spite of a lower risk of SIDS in twins compared with singletons for each birth weight group <3000 g, one component of the higher crude relative risk of SIDS in twins is attributable to the higher proportion of twins that are of low birth weight. A second component is the higher risk in twins compared with singletons for those of birth weight > or =3000 g. Like sex are at no greater risk than unlike sex twins, which suggests that zygosity is not a significant factor in SIDS.

Chi-Square Distribution↗
PubMed2002

Effects of cognitive, motor, and sensory disabilities on survival in cerebral palsy.

BACKGROUND: Cerebral palsy presents with a range of severity of cognitive, motor, and sensory disabilities, which might affect survival. AIMS: To quantify the effects of motor, cognitive, and sensory disabilities, year of birth, birth weight, and gestational age on survival in cerebral palsy. METHODS: A cohort of children with cerebral palsy born between 1966 and 1989 to mothers resident in a defined geographical region was subdivided into early impairment (EICP: cerebral insult prenatally or within 28 days of birth) or late impairment (LICP: insult at least 28 days after birth). Deaths are notified by the National Health Service Central Register. Birth and disability details were obtained from clinical records. Survival analyses were carried out. RESULTS: Severe motor disability was associated with a 30 year survival of 42% and severe cognitive disability with a 30 year survival of 62%. Severe visual disability was associated with a 30 year survival of 38%, but the association of survival with hearing disability was weak. EICP had better survival than LICP but the difference was not significant after allowing for severity of functional disabilities. Normal birth weight infants (>/= 2500 g) showed no birth cohort effect, but the 10 year survival of low birth weight (<2500 g) infants declined from 97% for 1966 to 89% for 1989 births. CONCLUSIONS: Survival in cerebral palsy varies according to the severity and number of functional disabilities and by birth weight. Among low birth weight children, survival declined steadily from 1966 to 1989 after allowing for disability. The disabilities reported do not capture all the factors affecting survival of preterm infants.

Adolescent↗
PubMed2001

Twins and cerebral palsy.

In a national follow-up study of twin births, monozygous compared with dizygous twins were at significantly increased for both to die in utero, one to die in utero and the co-twin to die in infancy, or both to be livebirths but both die in infancy. The prevalence of cerebral palsy among survivors of a co-twin fetal death was 80.2 and other cerebral impairment was 107.0 per 1000. Many apparently singleton cases of cerebral palsy and impairment may be due to fetal death of a twin that has not been recognized or has been recognized but not registered.

Cerebral Palsy↗
PubMed2001

Dermatoglyphic patterns, very low birth weight, and blood pressure in adolescence.

AIMS: To test the null hypotheses that finger and palm prints have no relation with fetal growth or adolescent blood pressure. METHODS: All 128 singleton, unimpaired, very low birth weight (VLBW; < or =1500 g) infants born to mothers resident in the county of Merseyside in 1980 and 1981 were studied retrospectively. The comparison group consisted of 128 age, sex, and school matched children. Main outcome measures were blood pressure at age 15 years, birth weight ratio, fingerprint patterns, and palmar AtD angles. RESULTS: The VLBW index population had a significantly higher systolic blood pressure than the comparison group (mean difference 3.2 mm Hg). The difference in diastolic blood pressure between the VLBW index and the matched comparison group was not significant. No significant differences were found in the palmar AtD angles or in the fingerprint proportions of arches, loops, and whorls and no correlation was found between fingerprint patterns and blood pressure. Among the VLBW index population, both height and right palmar AtD angle were independently and significantly correlated with and explained 12.1% of the variance in the systolic blood pressure. Birth weight ratio, as a measure of fetal growth restriction, had no significant correlation with systolic blood pressure. CONCLUSIONS: The higher systolic blood pressure of adolescents who were of very low birth weight compared with the matched comparison group is not associated with fingerprint patterns or birth weight ratio as markers for fetal growth restriction.

Adolescent↗
PubMed2001

Cerebral palsy in the surviving twin associated with infant death of the co-twin.

BACKGROUND: Monozygotic twins are at greater risk of dying and of serious morbidity than dizygotic twins, and both are at greater risk than singletons. This is only partly explained by the higher proportion of low birthweight infants among twins. AIM: To compare, in same sex and different sex twins, birth weight specific neonatal death rates and cerebral palsy prevalence rates in the surviving twin when the co-twin has died in infancy. METHODS: Analysis of birth and death registration data for same sex and different sex twins for England and Wales 1993-1995 where both were live births. Death certificates of all liveborn twins who died were obtained from the Office for National Statistics. A questionnaire was sent to the general practitioners of all surviving co-twins to determine if the child had any disability. RESULTS: The neonatal death rate in same sex twins was 25.4 and in different sex twins 18.0 per 1000 live births (death rate difference 7.4; 95% confidence interval 4.7 to 10.1; p < 0.001). The higher neonatal death rate in same sex compared with different sex twins is attributable to the higher proportion of same sex twins with low birth weight. Prevalence of cerebral palsy in the low birthweight group (< 1000 g) was marginally higher in same sex (224 per 1000) than different sex (200 per 1000) twin survivors. In the birth weight group 1000-1999 g, same sex twin survivors were at a significantly higher risk of cerebral palsy than those of different sex: 167 v 21 per 1000; difference 145 (95% confidence interval 44 to 231; p < 0.01) per 1000 infant survivors. CONCLUSION: There are two components to the cause of cerebral palsy in twins. Immaturity per se predisposes to cerebral damage. Also, same sex twins may sustain cerebral damage that is in excess of that due to immaturity.

Birth Weight↗
PubMed2001

The effects of assisted reproduction on the trends and zygosity of multiple births in England and Wales 1974-99.

Assisted reproductive techniques have led to an increase in the proportion of maternities that are multiple. Though predominantly dizygotic, they are at greater risk of monozygotic division than those spontaneously conceived. England and Wales data 1974-99 on stillbirths and livebirths were analysed for 4 periods: 1974-80 (pre-assisted reproduction; 1982-8; 1989-91 (pre-redefinition of stillbirth); 1993-9 (post-redefinition of stillbirth). For twin data, Weinberg's rule was applied to estimate the proportions that were mono- (MZ) and dizygotic (DZ). Compared with the period before assisted reproduction, the most recent period shows an increase in twin maternities of 3.81 per 1,000 comprised of 3.22 (95% CI 3.10 to 3.33; p < 0.0001) DZ and 0.60 (95% CI 0.51 to 0.68; p < 0.0001) MZ twins. It is estimated that 15.7% of assisted reproduction twins are MZ. Higher order multiple births showed an increase of 3.06 (95% CI 2.85 to 3.29; p < 0.0001) per 10,000 maternities. Stillbirth rates in MZ twins are of the same order of magnitude as those in higher order multiple births but higher than those in DZ twins. The improvement in stillbirth rates over the 26 year study period is of the same order magnitude in singletons, DZ and MZ twins and higher order multiples. Assisted reproduction has led to a significant increase in the proportion of MZ twins. These are at high risk of fetal death and this needs to be considered when local stillbirth and perinatal mortality rates are used in auditing obstetric services.

England↗
PubMed2000

Consequences of in-utero death in a twin pregnancy.

BACKGROUND: Twins have a higher mortality and morbidity than singletons and, among twins, the surviving co-twin of a fetus that dies in utero is particularly at risk. We did a cohort study to quantify mortality and serious morbidity in co-twin survivors of fetuses that died in utero. METHODS: We collected data of all registered twin births in England and Wales between 1993 and 1995 in which one twin was registered as having died in utero. Copies of all death certificates of these fetuses and death certificates of live-born co-twins of fetuses that died in utero were obtained from the Office for National Statistics. A questionnaire was sent to the general practitioners of all surviving co-twins to find out if the child had any disability. FINDINGS: There were 434 fetal death/live-birth same-sex twin pairs. Among the live births, there were 59 neonatal deaths, seven postneonatal deaths (first 28 days), and five infant deaths (<1 year). In three of the five deaths, the cause of death was cerebral palsy. Ten of the children who survived infancy were lost to follow up. Responses were received from general practitioners for 241 of 353 survivors (68% response). Of the 241 respondents, 23 had cerebral palsy and 28 had other cerebral impairment. Among the children who survived to infancy, the prevalence of cerebral palsy was 106 (95% CI 70-150) per 1000 and prevalence of other cerebral impairment was 114 (80-160) per 1000. There were 163 fetal death/live-birth different-sex twin pairs. Of the live births, 13 died in the neonatal period and four were lost to follow up. Of the 146 survivors, responses were received from the general practitioners for 102 (70% response). Three of the 102 had cerebral palsy and 12 had other cerebral impairment. The prevalence of cerebral palsy was 29 (95% CI 6-83) per 1000 and of other cerebral impairment 118 (62-196) per 1000 infant survivors. INTERPRETATION: The live-birth co-twin of a fetus that died in utero is at increased risk of cerebral impairment, the overall risk is 20% (95% CI 16-25). The gestational-age-specific prevalence of cerebral palsy after fetal death of the co-twin is much higher than that reported for the general twin population.

Brain Injuries↗
PubMed2000

Errors in registered birth weight and its implications for mortality statistics.

BACKGROUND: Birth weight mortality statistics are important for examining trends and monitoring the outcomes of neonatal care. AIM: To determine the effects of errors in the registered birth weight on birth weight specific mortality. METHODS: All twins born in England and Wales during 1993-95 comprise the denominator population. For those twins that died, the Office for National Statistics (ONS) provided copies of the death certificates. From the information on the death certificates, the registered birth weight was validated and amended using predetermined rules. The neonatal, postneonatal, and infant mortality rates were recalculated. RESULTS: In 2.5% of cases the registered birth weight was "not stated" and in others there were miscoding errors. Important differences between published and amended birth weight specific mortality rates especially in <500 g and >/=3500 g groups were evident. CONCLUSIONS: The bias arising from these errors should be taken into account in interpreting mortality rates and their trends.

Birth Weight↗
PubMed1999

The influence of prematurity and low birthweight on transplacental antibody transfer in Sri Lanka.

The influence of gestational age, the neonate's birthweight, and maternal age, weight, height and parity on transplacental antibody transfer was assessed in 141 mothers from Sri Lanka and their neonates. Paired blood samples were collected from the mothers and the umbilical cords of the newborns. The sera separated from these samples were categorized as: preterm but adequate birthweight (< 37 weeks' gestation and birthweight > or = 2500 g); term but low birthweight (> or = 37 weeks' gestation and birthweight < 2500 g); or term and adequate birthweight (> or = 37 weeks' gestation and birthweight > or = 2500 g). Neonatal and maternal sera were assessed, in ELISA, for specific IgG antibodies against measles virus (MeV), herpes simplex virus type-1 (HSV1), respiratory syncytial virus (RSV), varicella-zoster virus (VZV), tetanus toxoid (TT), diphtheria toxoid (DT), and Streptococcus pneumoniae (Pn) and Haemophilus influenzae type-b (Hib) capsular antigens. Placental antibody transfer to certain antibody specificities was significantly lower in preterm neonates than term neonates. Thus the ratios between geometric mean cord antibody levels and geometric mean maternal antibody levels (the antibody-transfer ratios) were lower in preterm sera than term sera, for MeV (1.51 v. 2.03; P = 0.03), HSV1 (1.29 v. 1.76; P = 0.04), VZV (0.96 v. 2.50; P = 0.01), TT (1.13 v. 1.33; P = 0.04), DT (1.03 v. 2.39; P = 0.02), Pn (0.68 v. 0.98; P = 0.01) and Hib (0.58 v. 0.98; P = 0.00). Geometric mean levels of antibody to MeV, VZV, TT, DT and Pn were also significantly lower in preterm neonates than term. Compared with the values for 'adequate-birthweight' sera, low birthweight was independently associated with significantly lower levels of antibody transfer, for MeV (with antibody-transfer ratios of 1.51 v. 2.03; P = 0.02), VZV (0.99 v. 2.50; P = 0.03), TT (1.01 v. 1.33; P = 0.04) and DT (1.16 v. 2.39; P = 0.04) and significantly lower levels of antibodies to MeV, HSV1, VZV, TT, DT and Pn in the neonates. Maternal age, weight, height and parity had no independent influence on placental IgG transfer for antibodies to any of the pathogens investigated. These results demonstrate that prematurity and low birthweight may influence the level of maternally acquired immunity in Sri Lankan neonates.

Antibodies, Bacterial↗
PubMed1999

Cause of death in cerebral palsy: a descriptive study.

BACKGROUND: Cause specific research on death certification in chronic disease has rarely involved cerebral palsy. AIMS: To evaluate cause of death information in people known to have cerebral palsy by: describing the cause of death distribution; determining case ascertainment using death certification as the data source; and analysing the choice of wording and its arrangement in the "cause of death statement". STUDY CASES AND SETTING: People with early or late impairment cerebral palsy who died by 30 June 1998, on the population based Mersey Cerebral Palsy Register born 1966-91 to mothers resident locally. STUDY DESIGN: Descriptive study of the multiply coded cause of death statements from National Health Service Central Register flagging. RESULTS: Death certificate copies were acquired for all 282 (13.4%) of the 2102 registered cases who died. Cerebral palsy was the most common "underlying cause of death" (95 of 282; 33.7%) and was mentioned in a further 61 cases. The underlying cause of death was more likely to be cerebral palsy with increasingly severe disability and was derived from Part II in 16 of 95 cases. CONCLUSIONS: The potential of death certification for case ascertainment of cerebral palsy is important, but limited, even with multiple cause coding. Mortality data need careful interpretation as a proxy source for examining trends and patterns in cerebral palsy.

Adolescent↗
PubMed1999

Fetal and infant death in mono- and dizygotic twins in England and Wales 1982-91.

AIM: To quantify the level of risk for stillbirth and infant death in singleton compared with twin pregnancies, using national data; to determine the independent effects of zygosity, sex, and birthweight on these risks in twin pregnancies. METHODS: A retrospective national study was carried out of all singleton and twin birth and death registrations in England and Wales 1982-91, according to sex and birthweight group. Weinberg's rule was applied to the twin pairs to differentiate mono- from dizygotic twins. Relative risks for mono- compared with dizygous twins for both twins being stillbirths and for one of the pair being a stillbirth were determined. For twins where one was stillborn and the other live born, the relative risk of neonatal and infant mortality in the surviving co-twin was determined. RESULTS: There were 6 563 834 registered singletons and 70772 registered twin pairs for the period under study. Monozygotic twins had a relative risk of: 18.91 (95% CI 12.48-28.64) for both twins being stillborn; 1.63 (95% CI 1.48-1.79) for one twin being a stillbirth; and 2.26 (95% CI 1.45-3.52) for the live born co-twin dying as a neonate. When both twins were live born and among singletons, the odds ratio for neonatal mortality of being male was 1.41 (95% CI 1.37-1.45) and there was a highly significant negative association with birthweight. After adjusting for birthweight group and sex, twins had a reduced neonatal mortality compared with singletons: odds ratio 0.91 (95% CI 0.85-0.96). CONCLUSIONS: Fetal death in one of monozygotic twins has serious implications for survival of the co-twin. Monochorionicity is probably the essential feature of the increased risk to the co-twin. It is imperative that all fetal deaths in multiple pregnancies are recorded and chorionicity determined if parents are to be adequately counselled.

Birth Weight↗
PubMed1999

Longitudinal study of behaviour disorders in low birthweight infants.

AIM: To compare the prevalence of childhood and adolescent behavioural problems in low birthweight infants with matched controls. METHODS: A cohort study of a geographically defined population of survivors of </=1500 g birthweight born in 1980 and 1981 and age, sex, and school matched controls was undertaken. Children with a clinical disability were excluded. Data from Rutter questionnaires, completed by parents and teachers when the children were aged 8 and again at age 14 years, were assessed. RESULTS: From an initial 40 321 births in 1980-81 there were 399 of birthweight </=1500 g, of whom 219 survived to age 8. After exclusion of the 42 children with clinical disability, 177 cases comprised the sample. Of these, 10 (6%) refused or could not be contacted, leaving 167 cases for each of whom a matched control was obtained. At age 14 years, both parent and teacher questionnaires showed an increased prevalence of behavioural problems in cases compared with controls. The presence of a pervasive behavioural problem, when the responses of parents and teachers were concordant, was present in 9% of cases and 3% of controls. There were 132 pairs where the cases and controls were the same at ages 8 and 14 years and provided longitudinal data. The parental questionnaire showed there was a significant decrease in the prevalence of behavioural problems for cases and controls between the ages of 8 and 14 years. There was almost no longitudinal change in the prevalence of behavioural problems as shown by the teacher questionnaires. CONCLUSION: Although low birthweight infants are at increased risk of behavioural problems, because they comprise only a small proportion of all births, their population attributable risk for behavioural disorder is around 2-3%.

Adolescent↗