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Biomedical subjects

O G Brooke

Publications and source records attributed to O G Brooke.

At least 19 recordsLinked to original sources
PubMed1991

The effect of nutritional intake on outcome of pregnancy in smokers and non-smokers.

The relationship between nutrient intake and pregnancy outcome (adjusted birth weight and gestational age) was investigated in randomly selected non-smokers (n97) and in heavy smokers (15 + cigarettes/d) (n72) booking for ante-natal care at a hospital in South London. Weighted dietary intakes (7d) were obtained at 28 and 36 weeks gestation. Birth weight was adjusted for gestational age, maternal height, parity and sex of infant. Compared with non-smokers, intakes of micronutrients and fibre were lower in smokers at both 28 and 36 weeks, and smokers reduced their intakes more in late pregnancy. The babies of smokers had a lower adjusted birth weight but there was no difference in length of gestation between smokers and non-smokers. After controlling for smoking, social class and alcohol consumption, nutrient intakes at 28 weeks were found to have no effect on adjusted birth weight. However, intakes of protein, zinc, riboflavin and thiamin at 36 weeks, and the change in intakes of these nutrients (plus iron) between 28 and 36 weeks, had independent positive effects on birth weight. Some of the effect of smoking on birth weight appeared to be mediated through differences in nutrient intakes. Smoking explained 14.3% of the variance in birth weight in this population and a further 2.4-7.2% was explained by change in nutrient intakes between 28 and 36 weeks. It is recommended that women in pregnancy do not reduce their dietary intakes in late pregnancy.

Analysis of Variance↗
PubMed1991

Cigarette smoking and birthweight: type of cigarette smoked and a possible threshold effect.

The effects on birthweight of the number of cigarettes smoked and their tar, nicotine and carbon monoxide yields were investigated prospectively in 1309 pregnant women of whom 414 were smokers. Several approaches to modelling the effect of smoking were tried. These suggested that while both yield and quantity smoked were important, yield had the greatest effect. This led to an empirical approach whereby consistent smokers were divided into four categories according to whether they smoked a low or high quantity of cigarettes per day and whether they smoked low or high yield cigarettes. Using these four groups it emerged that women smoking a low quantity of low yield cigarettes had babies of a similar mean birthweight to those of non-smokers whereas those smoking a low quantity of high yield cigarettes had babies whose birthweight was reduced to the same degree (6% or more) as those of mothers who smoked higher quantities. This apparent threshold was estimated as 13 cigarettes/day and 15 mg/cigarette carbon monoxide. We conclude that brand smoked is at least as important as quantity and that in this population there is evidence for a threshold for tobacco smoke intake below which no discernible effect on birthweight is seen.

Birth Weight↗
PubMed1991

The effects of smoking and drinking on the anthropometric measurements of neonates.

This study investigated the effects of smoking and alcohol consumption in pregnancy on length, head circumference, upper arm circumference and ponderal index, of neonates born to 1513 Caucasian women who delivered at St George's Hospital, south London. All measurements were adjusted for gestational age, maternal height, parity and sex of infant. Babies of smokers were shorter, had lower ponderal index and smaller upper arm circumference than those of non-smokers. After controlling for alcohol consumption, these differences remained (but with reduced statistical significance). There was no statistically significant difference in head circumference between smokers and non-smokers. Alcohol consumption at booking had no effect on growth measurements in non-smokers but had a significant, negative effect on all measurements in smokers. Drinking later in pregnancy had less effect. Alcohol appears to enhance the growth-retarding effect of smoking. It is suggested that both smoking and alcohol also have an inhibitory effect on fat deposition in babies, which contributes to the reduction in birthweight associated with smoking and drinking.

Alcohol Drinking↗
PubMed1990

Early diet of preterm infants and development of allergic or atopic disease: randomised prospective study.

OBJECTIVE: To study the effect of early diet on the development of allergic reactions in infants born preterm. DESIGN: Two randomised prospective trails. In trail A infants were randomly allocated banked donor milk or preterm formula as their sole diet or (separately randomised) as a supplement to their mother's expressed breast milk. In trial B infants were allocated term or preterm formula. A blind follow up examination was done 18 months after the expected date of birth. SETTING: Neonatal units of hospitals in Cambridge, Ipswich, King's Lynn, Norwich, and Sheffield. Outpatient follow up. PARTICIPANTS: 777 Infants with a birth weight less than 1850 g born during 1982 to 1984. MAIN OUTCOME MEASURES: Development of eczema, allergic reactions to food or drugs, and asthma or wheezing by nine and 18 months after term. Whenever possible the observations were confirmed by rechallenge or clinical examination. RESULTS: At 18 months after term there was no difference in the incidence of allergic reactions between dietary groups in either trial. In the subgroup of infants with a family history of atopy, however, those in trial A who received preterm formula rather than human milk had a significantly greater risk of developing one or more allergic reactions (notably eczema) by 18 months (odds ratio 3.6; 95% confidence interval 1.4 to 9.1). CONCLUSIONS: Feeding neonates on formulas based on cows' milk, including those with a high protein content, did not increase the overall risk of allergy. Nevertheless, in the subgroup with a family history of atopy early exposure to cows' milk increased the risk of a wide range of allergic reactions, especially eczema.

Animals↗
PubMed1990

Nutrient intakes during pregnancy: observations on the influence of smoking and social class.

The influence of smoking and social class on dietary intake in pregnancy was investigated in a random sample of smokers (greater than or equal to 15 cigarettes/d) and nonsmokers. A total of 206 subjects (94 smokers and 112 nonsmokers) completed a 7-d weighed dietary intake at 28 wk gestation and 178 completed a second assessment at 36 wk. Nonsmokers had higher intakes of almost all nutrients than did smokers and the nutrient density of their diet was greater. Energy intake was nonsignificantly higher in nonsmokers. Women in higher social classes had the highest nutrient intakes. Smokers were shorter than nonsmokers and tended to be of lower social class. After maternal height and social class were controlled for, smoking had a significant effect on intake of many micronutrients. Dietary intake was reduced in late pregnancy, particularly in smokers. These data suggest that smokers in all social classes have a poorer quality of diet.

Adult↗
PubMed1990

Maternal activity and birth weight: a prospective, population-based study.

To determine the association between maternal activity and pregnancy outcome, the authors investigated the separate influences of time, physical effort, and posture at work, both at a job and in the home, on birth weight. Study subjects were 1,507 of 1,889 women appearing consecutively for antenatal care at a district general hospital in inner London, England, in 1982-1984. Data were collected prospectively by interview and examination at several stages of pregnancy. Multivariable linear regression was used to distinguish associations with physical activity from confounding by other factors. The mean birth weight of infants born to women in full-time employment was 49 g less than that for births to women not in paid work (95 percent confidence interval (Cl) 1-97 g). However, the difference was due to confounding, and after adjustment, full-time employment was associated with a 12-g increase in birth weight (95 percent Cl -39 to 63 g). There was little difference in birth weight related to gestational stage at leaving work. Duration, physical effort required, and energy expenditure in paid work and in work at home had no discernible association with birth weight. A small increase in birth weight was associated with increased hours of sleep. These data allow estimates of associations with birth weight as precise as 80 g. Within the range of activities performed by pregnant women in the population studied, birth weight is unlikely to be associated with maternal physical activity.

Adolescent↗
PubMed1990

Birthweight ratio and outcome in preterm infants.

The association between birthweight ratio and outcome was investigated in 429 infants born before 31 weeks' gestation. Birthweight ratio was calculated in each case as birth weight divided by mean birth weight for gestation (from reference data). It was shown that a given ratio corresponded to the same birth centile across the gestational age range studied; a ratio of 0.8 corresponding to the 10th centile. There was a linear relationship between birthweight ratio and requirement for mechanical ventilation and postneonatal mortality. Birthweight ratio was also strongly and linearly related to body weight, length, and head circumference at 18 months' corrected age. Overall, there was no association between this ratio and neurodevelopmental outcome to 18 months. However, the subgroup with the largest weights for gestation (birthweight ratio greater than or equal to 1.1), had significantly higher language subscores than all the other children. Our data show that conventional dichotomous categorisation of preterm infants into small or appropriate for gestation is inadequate when exploring the association between size for gestation and outcome.

Birth Weight↗
PubMed1990

Food and drug reactions, wheezing, and eczema in preterm infants.

Allergic reactions were investigated in 777 preterm infants who were randomly assigned to early diet and followed up to 18 months post term. Wheezing or asthma was common (incidence 23%); it was associated with neonatal ventilation, maternal smoking, and a family history of atopy and was unexpectedly reduced in babies born by caesarean section. Even in non-ventilated infants, the incidence of subsequent wheezing was 18%, rising to an estimated 44% (using logistic regression) when the foregoing risk factors (excluding ventilation) were present. Eczema occurred in 151 infants (19%) and was strongly associated with multiple pregnancy (30% incidence in twins or triplets). Reactions to cows' milk (incidence: 4.4% from detailed history; 0.8% confirmed by challenge), other foods (10%), and drugs (5%) were within the range reported in full term infants. Milk and food reactions were associated with multiple pregnancy (19%) and a family history of atopy. Reactions to drugs were least likely to occur in infants who had been ventilated and were on multiple medications in the neonatal period, suggesting that drug tolerance may have developed. We speculate that preterm infants may be a high risk group for asthma and eczema, which could imply an association between atopy and prematurity.

Drug Hypersensitivity↗
PubMed1990

Social determinants of nutrient intake in smokers and non-smokers during pregnancy.

STUDY OBJECTIVE: The aim was to investigate the effects of social factors (education, income, marital status, partners' employment status, housing tenure, social class), smoking, and maternal height on the dietary intake of pregnant women. DESIGN: The study was a prospective investigation on a two phase sample. SETTING: The study involved women attending the antenatal clinic at a district general hospital. PATIENTS: A group of pregnant Caucasian women, selected because they were heavy smokers (15+ cigarettes/day) (n = 94) and a randomly selected sample of never smokers (n = 112) were studied. MEASUREMENTS AND MAIN RESULTS: Data on social factors were collected by interviewer administered questionnaire. A 7 day weighed intake method was used to determine dietary intake at 28 weeks gestation. In univariate analyses, income, housing tenure and social class had significant effects on intakes of both macro- and micronutrients, and maternal education and smoking had significant effects on intakes of micronutrients. Using a stepwise multivariate analysis with income, smoking and maternal education, income was a significant factor in the intake of most nutrients but this effect disappeared when social class and housing tenure factors were entered into the model. Only social class and housing tenure had any significant effect on intakes of macronutrients--energy, protein and fat. Smoking and maternal education were the most important determinants of quality of diet (nutrient density); other factors had only negligible effects. Income was the only significant factor in alcohol intake. It is suggested that the effects of social class and income are overlapping. CONCLUSIONS: Smoking, being renters of accommodation, and being of minimum education and low social class are risk factors for poor dietary intake. It is recommended that such higher risk groups be specifically targeted for nutritional advice in pregnancy.

Body Weight↗
PubMed1989

Effects on birth weight of smoking, alcohol, caffeine, socioeconomic factors, and psychosocial stress.

OBJECTIVE: To investigate the effects of smoking, alcohol, and caffeine consumption and socio-economic factors and psychosocial stress on birth weight. DESIGN: Prospective population study. SETTING: District general hospital in inner London. PARTICIPANTS: A consecutive series of 1860 white women booking for delivery were approached. 136 Refused and 211 failed to complete the study for other reasons (moved, abortion, subsequent refusal), leaving a sample of 1513. Women who spoke no English, booked after 24 weeks, had insulin dependent diabetes, or had a multiple pregnancy were excluded. MEASUREMENTS: Data were obtained by research interviewers at booking (general health questionnaire, modified Paykel's interview, and Eysenck personality questionnaire) and at 17, 28, and 36 weeks' gestation and from the structured antenatal and obstetric record. Variables assessed included smoking, alcohol consumption, caffeine consumption, and over 40 indicators of socio-economic state and psychosocial stress, including social class, tenure of accommodations, education, employment, income, anxiety and depression, stressful life events, social stress, social support, personality, and attitudes to pregnancy. Birth weight was corrected for gestation and adjusted for maternal height, parity, and baby's sex. MAIN RESULTS: Smoking was the most important single factor (5% reduction in corrected birth weight). Passive smoking was not significant (0.5% reduction). After smoking was controlled for, alcohol had an effect only in smokers and the effects of caffeine became non-significant. Only four of the socioeconomic and stress factors significantly reduced birth weight and these effects became non-significant after smoking was controlled for. CONCLUSIONS: Social and psychological factors have little or no direct effect on birth weight corrected for gestational age (fetal growth), and the main environmental cause of its variation in this population was smoking.

Adolescent↗
PubMed1989

High alkaline phosphatase activity and growth in preterm neonates.

In a study on 857 infants born preterm, high peak plasma alkaline phosphatase activity was independently related to slower growth rate in the neonatal period, and to a highly significant reduction in attained length at 9 months and 18 months post term. At 18 months the deficit in body length associated with peak neonatal plasma alkaline phosphase activity of 1200 IU/l or more was 1.6 cm (95% confidence interval 0.9 to 2.3 cm) after adjusting for confounding factors. The strength and magnitude of this association between high plasma alkaline phosphase activity and body length was greater than that for any other factor identified, including the infant's sex and the presence of fetal growth retardation. Data are presented that support the view that the high plasma alkaline phosphatase activity reflected early bone mineral substrate deficiency resulting in metabolic bone disease. We speculate that even silent early bone disease may interfere with the control of subsequent linear growth and emphasise the potential importance of providing preterm infants, especially those fed human milk, with adequate substrate for bone mineralisation.

Alkaline Phosphatase↗
PubMed1988

Is the raised metabolic rate of the small for gestation infant due to his relatively large brain size.

Oxygen consumption at different stages of vigilance, and for the whole 24 h, was measured in 13 small-for-gestational age (SGA) and 16 appropriate-for-age (AGA) premature infants at ages of 4-25 days. Brain weight was calculated from head circumference measurements and expressed as percentage of body weight and was found to be significantly higher in SGA infants than AGA ones (14% +/- 2.1 (S.D.) in the SGA and 12.3% +/- 1.5 (S.D.) in the AGA infants). Metabolic rate (MR) was calculated and expressed as kcal/centimetre head circumference, kcal/g brain wt. and kcal/kg body wt. Whereas MR expressed in kg body wt. was significantly higher in SGA infants than in AGA ones, no difference could be detected in the values when MR was expressed as kcal/cm head circumference, or MR/g brain wt. The difference that exists in the metabolic rates between SGA and AGA infants can be minimised by using head circumference as a reference. Therefore, the apparently high MR found in SGA infants in the neonatal period can be attributed, in a major way, to their relatively large brain size.

Brain↗
PubMed1987

Plasma amino acids in small preterm infants fed on human milk or formula.

Plasma amino acids were measured in 35 preterm infants, of whom 11 weighed less than 1000 g and 24 weighed between 1000 g and 1500 g at the time of sampling. Repeat samples were obtained in 18 at least seven days later. Seventeen infants were fed with preterm formula milk and 18 with expressed maternal breast milk at one to two hourly intervals during the study period. Formula fed infants gained weight faster than those fed on breast milk but there was little difference in amino acid patterns. Infants fed on breast milk were more likely to have concentrations of essential amino acids below the mid trimester fetal range than formula fed infants, but few infants in either feeding group had values above the fetal range. Those that did were equally distributed between both groups. Only two samples approached toxic concentrations, both in the group fed breast milk. The ratio of branched chain to aromatic amino acids was higher in the group fed on formula after correction for post conceptional age, implying that liver maturation may be accelerated by formula feeding. No correlations were found between plasma amino acid concentrations and nitrogen retention or metabolisable energy intake.

Amino Acids↗
PubMed1987

Energy and nitrogen balances in very low birthweight infants.

Energy and nitrogen balances were performed in 12 very low birthweight infants fed on either human milk or on a preterm formula. Energy and nitrogen retention were significantly higher in those given the formula feed (p less than 0.05). Highly significant correlations were found between nitrogen intake and nitrogen retention and between energy retention and nitrogen retention (p less than 0.001). Multiple regression analysis failed to show any effect of energy retention on the correlation between nitrogen intake and nitrogen retention in babies fed on human milk. Protein deficiency seems to be the most likely explanation of poor growth in infants fed on human milk.

Animals↗
PubMed1987

Human milk and preterm formula compared for effects on growth and metabolism.

Metabolic tolerance to a 'premature formula' feed was studied in a group of small immature infants, mean (SD) gestation 27.8 (1.4) weeks. Ten infants weighing 880-1295 g at the time of the study were fed on SMA low birthweight formula for a mean (SD) of 23.5 (5.5) days and were compared with 10 who were fed on expressed breast milk for 25.8 (6.1) days. The infants were well matched for weight, gestation, and postnatal age at the time of the study and were receiving full enteral feeds. They were investigated by balance techniques and plasma sampling on at least two occasions. Ten larger infants weighing 1330-1740 g and being fed on the same formula feed were also studied as an additional control group. Formula fed infants retained more nitrogen and gained weight faster. Plasma phosphorus concentrations were higher in the group fed on the formula feed, and alkaline phosphatase activity was lower. There were no significant differences in plasma concentrations of urea, electrolytes, or albumin or in acid base status. Taurine and arginine concentrations were higher in the group being breast fed, but there were no other significant differences in plasma amino acids, and no toxic concentrations occurred after either feed. The results of this study show that this formula (and presumably other feeds of similar composition) seem to be metabolically safe for the smallest infants.

Anthropometry↗