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Biomedical subjects

D M Becroft

Publications and source records attributed to D M Becroft.

At least 37 records · Page 2Linked to original sources

Risk factors for small for gestational age infants: a New Zealand study. New Zealand Cot Death Study Group.

AIM: The aim was to identify risk factors for small for gestational age infants. METHOD: Case-control study. The study population was 1800 infants selected randomly from all babies born over a three year period over 78% of the country. Of these 1800 infants, 85 (4.8%) were classified as preterm (< 37 weeks completed gestation) and were excluded. 157 (8.9%) were classified as small for gestational age (cases) and 1519 (86.3%) were fullterm, nonsmall for gestational age infants (controls). Risk factors were investigated using data collected from obstetric records and parental interviews. RESULTS: Risk factors associated with small for gestational age after controlling for potential confounders included maternal smoking during pregnancy (Odds ratio (OR) 2.61, 95% confidence interval (CI) 1.65, 4.15), primiparity (OR 2.96, 95% CI 1.59, 5.48), lack of antenatal care in the first trimester (OR 1.83, 95% CI 1.13, 2.98) and young age when mother left school (OR 1.56, 95% CI 1.01, 2.41). Use of marijuana in pregnancy significantly increased risk of small for gestational age at the 6% level (OR = 1.86, 95% CI 0.98, 3.52). The population attributable risk for maternal smoking was 31.1% (95% CI 18.2, 41.9). CONCLUSION: Maternal smoking was the most important modifiable risk factor in this dataset for small for gestational age.

Adolescent↗

Travel and changes in routine do not increase the risk of sudden infant death syndrome.

We investigated the relationship between travel and changes in routine and the sudden infant death syndrome (SIDS) among 485 SIDS cases compared with 1800 randomly selected control infants. There was no increased risk of SIDS with travel. Special events, such as christenings, were not associated with an increased risk of SIDS. However, visits to and by friends or relatives were associated with a significantly reduced risk of SIDS after controlling for potential confounders (odds ratios = 0.70; 95% confidence interval = 0.52, 0.96). These findings may indicate less social support in SIDS cases.

Analysis of Variance↗

Beckwith-Wiedemann syndrome, placental abnormalities, and gestational proteinuric hypertension.

BACKGROUND: Beckwith-Wiedemann syndrome is a genetically complex congenital disorder with variable clinical features at birth, including malformations, excessive body and/or organ growth, and endocrine dysfunction. Both maternal gestational proteinuric hypertension and placental abnormalities have been reported infrequently in Beckwith-Wiedemann syndrome, but the occurrence of three cases with both features at one institution within a year suggests that this may be an underreported association. CASES: Severe gestational proteinuric hypertension in three women led to termination of one pregnancy at 22 weeks' gestation, delivery by cesarean in another at 27 weeks of an infant who had hyperinsulinism and died at age 3 days, and stillbirth at 31 weeks in the third. All three infants had features diagnostic of Beckwith-Wiedemann syndrome. Placentomegaly had been identified by ultrasound in each case and was determined pathologically as mainly attributable to stromal expansion of the villous tree. Cysts resulting from hydrops in stem villi were identified ultrasonographically in one placenta; this lesion may be specific for Beckwith-Wiedemann syndrome. The third placenta was associated with a discrete complete hydatidiform mole. CONCLUSIONS: A diagnosis of Beckwith-Wiedemann syndrome should be considered in all cases in which gestational proteinuric hypertension is associated with ultrasound findings of placentomegaly, with or without associated cystic changes in the placenta, and an examination should be made for other confirmatory features.

Adult↗

Bed sharing, smoking, and alcohol in the sudden infant death syndrome. New Zealand Cot Death Study Group.

OBJECTIVES: To investigate why sharing the bed with an infant is a not consistent risk factor for the sudden infant death syndrome in ethnic subgroups in New Zealand and to see if the risk of sudden infant death associated with this practice is related to other factors, particularly maternal smoking and alcohol consumption. DESIGN: Nationwide case-control study. SETTING: Region of New Zealand with 78% of all births during 1987-90. SUBJECTS: Home interviews were completed with parents of 393 (81.0% of total) infants who died from the sudden infant death syndrome in the postneonatal age group, and 1592 (88.4% of total) controls who were a representative sample of all hospital births in the study region. RESULTS: Maternal smoking interacted with infant bed sharing on the risk of sudden infant death. Compared with infants not exposed to either risk factor, the relative risk for infants of mothers who smoked was 3.94 (95% confidence interval 2.47 to 6.27) for bed sharing in the last two weeks and 4.55 (2.63 to 7.88) for bed sharing in the last sleep, after other confounders were controlled for. The results for infants of non-smoking mothers were inconsistent with the relative risk being significantly increased for usual bed sharing in the last two weeks (1.73; 1.11 to 2.70) but not for bed sharing in the last sleep (0.98; 0.44 to 2.18). Neither maternal alcohol consumption nor the thermal resistance of the infant's clothing and bedding interacted with bed sharing to increase the risk of sudden infant death, and alcohol was not a risk factor by itself. CONCLUSION: Infant bed sharing is associated with a significantly raised risk of the sudden infant death syndrome, particularly among infants of mothers who smoke. The interaction between maternal smoking and bed sharing suggests that a mechanism involving passive smoking, rather than the previously proposed mechanisms of overlaying and hyperthermia, increases the risk of sudden infant death from bed sharing.

Adult↗

Ethnic differences in mortality from sudden infant death syndrome in New Zealand.

OBJECTIVES: To examine the factors which might explain the higher mortality from sudden infant death syndrome in Maori infants (7.4/1000 live births in 1986 compared with 3.6 in non-Maori children). DESIGN: A large nationwide case control study. SETTING: New Zealand. 485 infants who died of sudden infant death syndrome were compared with 1800 control infants. There were 229 Maori and 240 non-Maori cases of sudden infant death syndrome (16 cases unassigned) and 353 Maori and 1410 non-Maori controls (37 unassigned). RESULTS: Maori infants had 3.81 times the risk (95% confidence interval 3.06 to 4.76) of sudden infant death syndrome compared with non-Maori infants. The risk factors for sudden infant death syndrome within groups were remarkably similar. When Maori and non-Maori controls were compared the prevalence of many of the known risk factors was higher in Maori infants. In particular, mothers were socioeconomically disadvantaged, younger, and more likely to smoke and their infants were of lower birth weight and more likely to share a bed with another person. Multivariate analysis controlling for potential confounders found that simply being Maori increased the risk of sudden infant death syndrome by only 1.37 (95% CI = 0.95 to 2.01), not statistically significantly different from 1. Population attributable risk was calculated for prone sleeping position, maternal smoking, not breast feeding, and infants sharing a bed with another person. In total these four risk factors accounted for 89% of deaths from sudden infant death syndrome in Maori infants and 79% in non-Maori infants. CONCLUSION: The high rate of sudden infant death syndrome among Maori infants is based largely on the high prevalence in the Maori population of the major risk factors. Other risk factors, not related to ethnicity, probably explain remaining differences between Maori and non-Maori children.

Birth Weight↗

Constitutional relaxation of insulin-like growth factor II gene imprinting associated with Wilms' tumour and gigantism.

We have examined the imprinting of the insulin-like growth factor II gene (IGF2) in ten normal kidney samples from children with renal embryonal neoplasms. In kidney samples from nine children with normal growth profiles, IGF2 mRNA was transcribed monoallelically, consistent with normal imprinting of the gene. But in one child who had generalized somatic overgrowth, IGF2 was transcribed from both alleles in her kidney, peripheral blood leukocytes and Wilms' tumour. These findings suggest that a defect in genomic imprinting can occur constitutionally, leading to growth abnormalities and predisposition to Wilms' tumour.

Alleles↗

Breastfeeding and the risk of sudden infant death syndrome.

The New Zealand Cot Death Study, a multicentre case-control study, was set up to identify risk factors associated with sudden infant death syndrome (SIDS). In the 3 years of the study there were 485 infant deaths classified as SIDS in the study areas and 1800 infants who were randomly selected as controls. Data were collected by parent interviews and from obstetric notes. A full set of data for this analysis was available from 356 cases and 1529 control infants. The relationship between length of any breastfeeding and SIDS was examined: 92% of the controls were initially breastfed compared to 86% of the cases. As time went by, cases stopped breastfeeding sooner than controls: by 13 weeks, 67% controls were breastfed versus 49% cases. A reduced risk for SIDS in breastfed infants persisted during the first 6 months after controlling for confounding demographic, maternal and infant factors. Infants exclusively breastfed 'at discharge from the obstetric hospital' (odds ratio [OR] = 0.52, 95% confidence interval (CI): 0.35-0.71) and during the last 2 days (OR = 0.65, 95% CI: 0.46-0.91) had a significantly lower risk of SIDS than infants not breastfed after controlling for potential confounders. We have shown a substantial association of breastfeeding with a lowered risk for SIDS. This supports the need for more positive promotion and active community support to further enhance the level and length of exclusive breastfeeding.

Breast Feeding↗

Dummies and the sudden infant death syndrome.

The association between dummy use and sudden infant death syndrome (SIDS) was investigated in 485 deaths due to SIDS in the postneonatal age group and compared with 1800 control infants. Parental interviews were completed in 87% of subjects. The prevalence of dummy use in New Zealand is low and varies within New Zealand. Dummy use in the two week period before death was less in cases of SIDS than in the last two weeks for controls (odds ratio (OR) 0.76, 95% confidence interval (CI) 0.57 to 1.02). Use of a dummy in the last sleep for cases of SIDS or in the nominated sleep for controls was significantly less in cases than controls (OR 0.44, 95% CI 0.26 to 0.73). The OR changed very little after controlling for a wide range of potential confounders. It is concluded that dummy use may protect against SIDS, but this observation needs to be repeated before dummies can be recommended for this purpose. If dummy sucking is protective then it is one of several factors that may explain the higher mortality from SIDS in New Zealand than in other countries, and may also explain in part the regional variation within New Zealand.

Case-Control Studies↗

Insulin-like growth factor II messenger ribonucleic acid expression in Wilms tumor, nephrogenic rest, and kidney.

BACKGROUND: Wilms tumors (WTs) are embryonic neoplasms of the kidney that are believed to arise from primitive metanephrogenic blastema. Our previous reports and those of others indicate that WTs show an increased expression of insulin-like growth factor II (IGF-II) mRNA. However, the precise role of IGF-II on Wilms tumorigenesis is not known. A central question is to determine whether the increased IGF-II expression in WTs simply reflects the fetal nature of WTs (effect), or is induced by specific changes in gene expression (cause). EXPERIMENTAL DESIGN: This study included 31 sporadic WTs, 7 fetal and 3 adult kidneys and 1 yolk sac tumor. Clinical and histologic summaries of WT cases are shown in Table 1. In WTs, the relative area of blastemal, epithelial, poorly differentiated spindle cell and heterologous cell components were assessed. Dot and Northern blot hybridization, using cDNA probes, were done to assess the level of IGF-II mRNA expression. In situ RNA hybridization was employed to localize IGF-II transcripts. Immunohistochemistry was applied to frozen sections to demonstrate cytokeratin and type-IV collagen. These results were then correlated with the histology of WTs and their precursor lesions, i.e., nephrogenic rests (NRs). RESULTS: Dot blot hybridization indicated that IGF-II transcripts were 32- to 64-fold more abundant in WTs than in the adjacent uninvolved kidneys. In situ hybridization showed that WTs, NRs, and fetal kidney shared a common feature in which IGF-II transcripts were predominantly associated with blastema. However, WTs and NRs differed from fetal kidney in that occasional epithelial structures and dense blastema showed aberrant, sustained IGF-II expression. CONCLUSIONS: The data indicate two points. 1) There is an inverse correlation between nephroblastic differentiation and IGF-II expression in developing fetal kidney. 2) The IGF-II expression in WTs and NRs does not simply reflect the embryonal nature of the tumor but is rather significantly altered, suggesting a role as a transforming growth factor in Wilms tumorigenesis.

Adolescent↗

Smoking and the sudden infant death syndrome.

OBJECTIVE: Maternal smoking has been shown to be a risk factor for sudden infant death syndrome (SIDS). The effect of smoking by the father and other household members has not previously been examined. METHODS: A large nationwide case-control study. Four hundred eighty-five SIDS deaths in the postneonatal age group were compared with 1800 control infants. RESULTS: Infants of mothers who smoked during pregnancy had a 4.09 (95% confidence interval [CI] = 3.28, 5.11) greater risk of death than infants of mothers who did not smoke. Infants of mothers who smoked postnatally also had an increased risk of SIDS compared with infants of nonsmokers and, furthermore, the risk increased with increasing levels of maternal smoking. Smoking by the father and other household members increased the risk (odds ratio [OR] = 2.41, 95% CI = 1.92, 3.02 and OR = 1.54, 95% CI = 1.20, 1.99, respectively). Smoking by the father increased the risk of SIDS if the mother smoked, but had no effect if she did not smoke. In analyses controlled for a wide range of potential confounders, smoking by the mother and father was still significantly associated with an increased risk of SIDS. CONCLUSION: Passive tobacco smoking is causally related to SIDS.

Case-Control Studies↗

Postnatal depression and SIDS: a prospective study.

This study was carried out in response to reports from nurses to a post-neonatal mortality review committee that a number of mothers of infants dying from sudden infant death syndrome (SIDS) appeared to be depressed before the child's death. The New Zealand Cot Death Study was a 3 year multicentre case-control study for SIDS. There were 485 SIDS cases in the post-neonatal age group in the study regions, and these were compared with 1800 control infants. Infants of mothers with either a self-reported use of medication for psychiatric disorders, a history of hospitalization for psychiatric illness or a family history of postnatal depression had a significantly increased risk of SIDS compared with infants of mothers who were either not using medication (odds ratio (OR) = 1.45; 95% confidence interval (CI) = 1.03, 2.04) or were without a history of hospitalization for psychiatric illness (OR = 1.80; 95% CI = 1.03, 3.11) or a family history of postnatal depression (OR = 1.61; 95% CI = 1.06, 2.43). All mothers of infants born in the study areas over a 1 year period were eligible to complete a questionnaire measuring maternal depression when the infant was 4 weeks of age. Thirty-three infants subsequently died from SIDS, and they were compared with 174 controls. Fifteen (45.5%) of the mothers of cases were depressed, compared with 28 (16.1%) of the mothers of controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Case-Control Studies↗

Four modifiable and other major risk factors for cot death: the New Zealand study.

New Zealand's high mortality rate from sudden infant death syndrome (SIDS) prompted the development of the New Zealand Cot Death Study. A report of the analysis of the data from the first year has been published. This report now gives the major identified risk factors from the full 3 year data set. In this case-control study there were 485 infants who died from SIDS in the post-neonatal age group, and 1800 control infants, who were a representative sample of all hospital births in the study region. Obstetric records were examined and parental interviews were completed in 97.5% and 86.9% of subjects, respectively. As expected many risk factors for SIDS were confirmed including: lower socio-economic status, unmarried mother, young mother, younger school-leaving age of mother, younger age of mother at first pregnancy, late attendance at antenatal clinic, non-attendance at antenatal classes, Maori, greater number of previous pregnancies, the further south the domicile, winter, low birthweight, short gestation, male infant and admission to a special care baby unit. In addition, however, we identified four risk factors that are potentially amenable to modification.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

Further evidence supporting a causal relationship between prone sleeping position and SIDS.

A 3 year case-control study identifying the risk factors for SIDS was undertaken. Preliminary analysis of the data from the first year suggested that SIDS mortality could fall by 50% if the prevalence of the prone sleeping position changed from 40 to 0%. During the 3 year study the prevalence of the prone sleeping position among infants has fallen from 43% in the first year to 20% in the third year. SIDS mortality has fallen to 3.1/1000 live births, which is very close to that predicted. When considered with other available evidence this strongly supports a causal relationship between the prone sleeping position and SIDS.

Case-Control Studies↗

Childhood cancer among the Polynesian population.

From June 1981 through June 1989, 95 Polynesian children were seen for initial care of malignancy at the Princess Mary Hospital for Children (PMHC). The incidence of malignancy in the Polynesian populations served, the histology of the malignancies, and the outcome of therapy were reviewed and compared with 185 non-Polynesian (non-P) patients seen during the same period. Incidence figures for Polynesians and non-P were similar, but histologic patterns differed, showing an increased occurrence of leukemia, particularly nonlymphoblastic leukemia, an increased occurrence of bone tumors, and a decreased incidence of central nervous system tumors for Polynesians. Survival for Polynesian children with acute lymphoblastic leukemia was worse than for non-P. Survival in all other disease categories was similar.

Child↗

Results from the first year of the New Zealand cot death study.

New Zealand's high mortality rate from the sudden infant death syndrome (SIDS) prompted the development of the New Zealand cot death study. This report of the preliminary analysis of the first year of the data gives the major identified risk factors. One hundred and sixty-two infants who died from SIDS were compared with 589 control infants, who were a representative sample of all hospital births in the study region. Obstetric records were examined and parental interviews were completed in 96% and 89% of subjects respectively. Data were available for all the variables in this study in 95% of those interviewed, thus 128 cases and 503 controls make up the subjects of this report. As expected we confirmed many risk factors for SIDS including: lower socioeconomic status, unmarried mother, young mother, younger school leaving age of mother, younger age of mother at first pregnancy, late attendance at antenatal clinic, nonattendant at antenatal classes, Maori, greater number of previous pregnancies, lower birth weight, shorter gestation, male infant, admission to neonatal intensive care unit. In addition, however, we identified three risk factors which are potentially amenable to modification. These were the prone sleeping position of baby (odds ratio = 3.53, 95% confidence interval 2.26, 5.54), maternal smoking (1-9 cigarettes/day OR = 1.87, 95% CI = 0.98, 3.54; 10-19/day OR = 2.64, 95% CI = 1.47, 4.74; 20+/day OR = 5.06, 95% CI = 2.86, 8.95) and breast feeding (OR = 2.93, 95% CI = 1.84, 4.67).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗