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D G Cook

Publications and source records attributed to D G Cook.

At least 19 recordsLinked to original sources
PubMed2000

Cholesterol and arterial distensibility in the first decade of life: a population-based study.

BACKGROUND: Blood cholesterol levels are a key determinant of coronary heart disease risk in adults, but the importance of lipid levels in the general population during childhood is less clear. We related arterial distensibility, a marker of vascular function known to be altered early in atherosclerosis, to the lipid profile of a population-based sample of children aged 9 to 11 years. METHODS AND RESULTS: A noninvasive ultrasound technique was used to measure arterial distension during the cardiac cycle in the brachial arteries of 361 children from 4 towns in the United Kingdom. This measure was related to their pulse pressure to assess arterial distensibility. All the children had previously had a comprehensive assessment of cardiovascular risk including a full lipid profile, cotinine-assessed smoke exposure, serum glucose, and questionnaire data on socioeconomic and dietary factors. Mean total cholesterol in the population was 4.72 [SD 0.75] mmol/L. There was a significant, inverse relation between cholesterol and distension of the artery across this range (linear regression coefficient -11.8 microm. mmol(-1). L(-1), P=0.003). Similar relationships were demonstrated with LDL and apolipoprotein B (-12.9 microm. mmol(-1). L(-1), P=0. 005 and -36.9 microm/mmol/L, P=0.01). HDL and triglyceride levels showed no consistent association with distensibility. CONCLUSIONS: LDL cholesterol levels had an impact on arterial distensibility in the first decade of life. Furthermore, the functional differences in the arterial wall were demonstrated within the lipid range found in normal children, a finding that raises the possibility that cholesterol levels in the general population during childhood may already be relevant to the development of vascular disease.

Adult↗
PubMed2000

Frequency and allelic association of common variants in the lipoprotein lipase gene in different ethnic groups: the Wandsworth Heart and Stroke Study.

The lower serum triglyceride (Tg), higher high density cholesterol (HDL-C) levels and low coronary heart disease (CHD) mortality in black populations, contrast with that in whites. By comparison, South Asian populations display a higher mortality from CHD associated with increased Tg and low HDL-C levels. Lipoprotein lipase (LPL) plays a major role in Tg metabolism. To determine if variation in the LPL gene contributes to the differences in lipid levels, we studied the frequencies and allelic associations of five common variants in the lipoprotein lipase (LPL) gene (-93T/G, D9N, N291S, S447X, and the HinddIII RFLP in intron 8) with serum Tg and HDL-cholesterol concentrations in population samples of middle-aged men and women of whites, South Asians, and blacks of African origin co-resident in South London. Significantly higher frequencies of the H(-) (P < 0.00001), N9 (P < 0.001), and -93G (P < 10(-10)) alleles were seen in blacks compared to the other two groups. Allelic association between -93G and N9, and H(+) and X447 was strong in all three groups. However, no association was observed between serum Tg and HDL-cholesterol concentrations and these variants in the three ethnic groups. A single common polymorphism in the LPL gene is unlikely to account for the differences in fasting serum Tg in populations of different ethnic background. The importance of the differences in frequencies and the mechanism(s) whereby these may contribute towards a beneficial LPL genotype in black populations remain to be determined.

Adult↗
PubMed2000

C-reactive protein concentration in children: relationship to adiposity and other cardiovascular risk factors.

Whether or not C-reactive protein (CRP) predicts heart disease in adults because it is a marker of damage or atherosclerosis is difficult to assess. In children, there is no confounding with coronary disease or active smoking. We measured CRP in 699 children aged 10-11 years. CRP levels were 47% higher in girls than boys, and rose with age by 15%/year. CRP levels were 270% (95% CI, 155-439%) higher in the top fifth than the bottom fifth of Ponderal index (weight/height(3)). After adjustment, CRP levels remained 104% (95% CI, 23-236%) higher in the 56 children of South Asian origin. CRP was unrelated to: birth weight, height, social class, Helicobacter pylori infection or passive smoke exposure. CRP was correlated with several cardiovascular risk factors, but only fibrinogen (r = 0.33, P = 0.0001), HDL-cholesterol (r = -0.13, P = 0.0006), heart rate (r = 0.12, P = 0.002) and systolic blood pressure (r = 0.08, P = 0.02) remained statistically significant after adjustment. We conclude that adiposity is the major determinant of CRP levels in children while physical fitness has a small independent effect. The strong relationships with fibrinogen and HDL-cholesterol suggest a role for inflammation throughout life in the development of atherosclerosis and cardiovascular disease. Longitudinal studies are needed to determine whether these associations reflect long term elevations of these risk factors in some individuals, or short term fluctuations in different individuals.

Age Distribution↗
PubMed2000

Western blotting is useful in the salivary diagnosis of Helicobacter pylori infection.

BACKGROUND: The salivary diagnosis of Helicobacter pylori infection offers attractive possibilities for the epidemiological study of infection in children. Salivary enzyme linked immunosorbent assay (ELISA) is less reliable then serum ELISA, owing to variable transudation of immunoglobulin. In addition, children are more difficult to study because of lower specific serum antibody concentrations to H pylori. The performance of salivary western blotting in comparison with serum western blotting and serum ELISA was investigated in school children. SUBJECTS AND METHODS: Paired serum and saliva specimens were obtained from 669 [corrected] school children aged 9-11 in 10 British towns. All saliva and serum specimens were first analysed by ELISA; subsequently, western blotting of both specimens was performed on 31 and 34 specimens, respectively, to establish the criteria for positivity for western blotting. The remaining 121 specimens were then tested blindly and saliva was compared with the serum. RESULTS: The sensitivity and specificity of salivary ELISA in the 669 [corrected] specimens was 32 of 50 (64%) and 530 of 619 (86%) [corrected], respectively, when compared with serum ELISA. The western blotting validation was performed on 28 subjects with positive serum and positive salivary ELISA, 28 saliva positives with negative serum, 16 saliva negatives with positive serum, and 50 doubly negative subjects. Compared with serum western blots, the sensitivity and specificity of salivary western blots was 38 of 47 (81%) and 68 of 75 (91%), respectively. Using serum ELISA as the gold standard, the sensitivity and specificity were 32 of 44 (73%) and 72 of 78 (92%), respectively, the specificity being significantly higher than salivary ELISA (p < 0.001). CONCLUSION: Salivary western blotting for IgG is useful in the diagnosis of H pylori infection and is superior to ELISA. It also permits the identification of pathogenic strains.

Blotting, Western↗
PubMed1999

Fibrinogen and factor VII levels are related to adiposity but not to fetal growth or social class in children aged 10-11 years.

Factors operating in fetal life or during childhood may be important in determining fibrinogen and factor VII concentrations in adult life, and particularly in explaining social gradients in cardiovascular disease risk. In 1994, the authors measured fibrinogen and factor VIIc levels in 641 children aged 10-11 years (61% response rate) from schools in five towns in England and Wales. Birth weight was obtained by maternal recall, and other data on measures of fetal growth were obtained from birth records. Fibrinogen levels were higher in girls (258.8 mg/dl) than in boys (245.4 mg/dl) (95% confidence interval (CI) for difference: 5.5, 21.5). Fibrinogen and factor VIIc levels were linearly related to adiposity, rising by 37.1 mg/dl (95% CI: 24.7, 49.5) and 13.0% of standard (95% CI: 6.3, 19.7), respectively, between the bottom and top quintiles of ponderal index (weight (kg)/height (m)3). Fibrinogen was independently related to heart rate (p < 0.001) and was negatively but nonsignificantly related to measures of physical activity. Factor VIIc was positively correlated with total cholesterol (p < 0.001). No relations were found with measures of fetal growth or social class. These data do not support the concept that fibrinogen or factor VII levels are determined in utero or by social factors in childhood. Adiposity and physical training appear to be the important determinants of fibrinogen and factor VII levels in childhood.

Adipose Tissue↗
PubMed1999

Explaining variation in hospital admission rates between general practices: cross sectional study.

OBJECTIVES: To quantify the extent of the variation in hospital admission rates between general practices, and to investigate whether this variation can be explained by factors relating to the patient, the hospital, and the general practice. DESIGN: Cross sectional analysis of routine data. SETTING: Merton, Sutton, and Wandsworth Health Authority, which includes areas of inner and outer London. SUBJECTS: 209 136 hospital admissions in 1995-6 in patients registered with 120 general practices in the study area. MAIN OUTCOME MEASURES: Hospital admission rates for general practices for overall, emergency, and elective admissions. RESULTS: Crude admission rates for general practices displayed a twofold difference between the 10th and the 90th centile for all, emergency, and elective admissions. This difference was only minimally reduced by standardising for age and sex. Sociodemographic patient factors derived from census data accounted for 42% of the variation in overall admission rates; 45% in emergency admission rates; and 25% in elective admission rates. There was a strong positive correlation between factors related to deprivation and emergency, but not elective, admission rates, raising questions about equity of provision of health care. The percentage of each practice's admissions to different local hospitals added significantly to the explanation of variation, while the general practice characteristics considered added very little. CONCLUSIONS: Hospital admission rates varied greatly between general practices; this was largely explained by differences in patient populations. The lack of significant factors related to general practice is of little help for the direct management of admission rates, although the effect of sociological rather than organisational practice variables should be explored further. Admission rates should routinely be standardised for differences in patient populations and hospitals used.

Cross-Sectional Studies↗
PubMed1999

The effects of adiposity and weight change on forced expiratory volume decline in a longitudinal study of adults.

OBJECTIVE: To investigate whether changes in anthropometric measures are related to lung function decline. DESIGN: A national 7-y follow up study in Great Britain. SUBJECTS: 3391 adults aged 18-73 y at baseline. MEASUREMENTS: The primary outcome measure was change in forced expiratory volume in one second (Delta FEV1), adjusted for age, height and sex. This was related to changes in weight, body mass index, waist circumference, hips circumference and waist to hip ratio. RESULTS: Changes in weight, body mass and waist circumference, adjusted for confounders including mean level, were all associated with changes in FEV1 (P<0.001), with all effects stronger in men than women (P<0.05). Change in waist to hip ratio was related in men (P=0.01), but not in women (P=0.34). A 10 kg weight increase induced an additional fall in FEV1 of 96 ml (95% confidence interval (95% CI 65-127 ml) in men, and 51 ml (95% CI. 27-75 ml) in women. In men, the effect increased with average weight and obesity and was more pronounced in middle age. This phenomenon was not present in women, possibly due to gender differences in weight distribution in later adult life. Smoking did not appear to influence the magnitude of effect in either sex. The detrimental effect of weight gain on FEV1 in subjects that stopped smoking between studies appeared small in comparison to the benefit of smoking cessation. CONCLUSION: Increases in adult body mass are predictors of FEV1 decline, especially among older and heavier men, where weight reduction may significantly slow lung function decline.

Adolescent↗
PubMed1999

Unemployment pre-dates symptoms of depression and anxiety resulting in medical consultation in young men.

BACKGROUND: There is evidence to support a link between unemployment and lower levels of psychological well-being, but debate continues as to whether unemployment results in psychological morbidity, or whether the association is due to those who are more vulnerable to mental illness becoming unemployed. Here we assess the effect of recent and accumulated unemployment in young men on the risk of developing depression and anxiety leading to medical consultation. Adjustment was made for a measure of pre-existing tendency to depression, behavioural maladjustment, social class, qualifications and region of residence. METHODS: Some 3241 men from the National Child Development Study (the 1958 British birth cohort) with data from birth to age 33 years, collected at birth and ages 7, 11, 16, 23 and 33 years were used in these analyses. The outcome measure was onset age of anxiety or depression between ages 24 and 33 years, that resulted in consultation with a GP or a specialist. This was used in Cox proportional hazards models where two measures of unemployment were modelled as time varying covariates. Pre-existing tendency to depression was measured by the Malaise Inventory prior to the experience of unemployment at age 23 years. Two measures of unemployment were investigated: any unemployment in the year prior to onset (recent unemployment) and all accumulated unemployment prior to onset (divided into four categories: 0, 1-12, 13-36 and 37+ months of unemployment). RESULTS: After adjustment for potential confounding factors including pre-existing tendency to depression, the relative risk (RR) for developing symptoms resulting in consultation was 2.10 (95% CI: 1.21-3.63), when those who were unemployed in the year prior to onset were compared with those who were not. Accumulated unemployment was not statistically significantly related to onset of symptoms in all men after adjustment for the potential confounding factors: an RR of 1.63 (95% CI: 0.95-2.79) for men with 37+ months of accumulated unemployment when compared with none. However, exclusion of men with a pre-existing tendency to depression indicated by the Malaise Inventory score, increased the RR to 2.30 (95% CI: 1.44-3.65) for recent unemployment and 2.04 (95% CI: 1.17-3.54) for 37+ months of accumulated unemployment when compared with none. CONCLUSIONS: Unemployment is a risk factor for psychological symptoms of depression requiring medical attention, even in those men without previous psychological vulnerability.

Adult↗
PubMed1999

Plasma vitamin C levels in men and women from different ethnic backgrounds living in England.

BACKGROUND: People of South Asian origin living in the UK have higher death rates due to coronary heart disease than whites. The reasons for these differences are not fully understood. Previous attempts to relate diet to cardiovascular risk in South Asians have been inconclusive. METHODS: We compared the levels of plasma vitamin C in a cross-sectional population-based study of 1018 men and women aged 40-59 (455 men, 563 women, 328 South Asians, 355 of African descent, 335 whites) co-resident in a geographically defined area of South London, when allowing for potential confounders. RESULTS: Fasting plasma vitamin C levels were significantly higher in women, vegetarians, supplement takers and non-smokers. After adjustment for age, body mass index, current smoking, supplement use and vegetarianism the mean plasma vitamin C levels were 38.8 (SE 1.6) mumol/l in white men, 36.5 (1.6) mumol/l in men of African descent and 32.9 (1.5) mumol/l in South Asian men (P = 0.033 by analysis of co-variance). In women the adjusted mean plasma vitamin C levels were 52.4 (1.6) mumol/l in whites, 46.0 (1.4) mumol/l in women of African descent and 37.3 (1.8) mumol/l in South Asians (P < 0.0001 by analysis of covariance). South Asians had lower levels than whites in both men (difference 6.4 [95% CI: 1.5, 11.3] mumol/l) and women (16.8 [95% CI: 11.5, 22.1] mumol/l). South Asian women, but not men, also had lower levels than those of African descent (8.8 [95% CI: 4.5, 13.1] mumol/l). African women, but not men, had lower levels than white women (6.6 [95% CI: 2.3, 10.9] mumol/l). No significant differences were seen between Caribbeans and West Africans or between South Asian Hindus and Muslims. CONCLUSIONS: These data suggest that important dietary differences in vitamin C exist between different ethnic groups living in England. The larger differences in South Asians may contribute to their increased coronary risk.

Adult↗
PubMed1999

A population study of ethnic variations in the angiotensin-converting enzyme I/D polymorphism: relationships with gender, hypertension and impaired glucose metabolism.

BACKGROUND: The presence of the deletion allele of the angiotensin-converting enzyme (ACE) I/D polymorphism is associated with an excess risk of vascular disease and diabetic nephropathy. OBJECTIVE: To examine the importance of this polymorphism as a determinant of hypertension and impaired glucose metabolism in a population-based study of three ethnic groups and assess the potential modifying effect of gender. DESIGN: Population-based cross-sectional study in South London. The population-based sample of 1577 men and women, age 40-59 years, was obtained from stratified random sampling of general practice lists where 25% of the residents were born outside the UK. The ACE I/D polymorphism was determined for 1366 individuals (86.6%): 462 whites, 462 of African descent and 442 of South Asian origin. RESULTS: The genotype frequency within each ethnic group was in Hardy-Weinberg equilibrium. The frequencies were similar in whites and those of African descent (II, ID, DD: 18.4%, 49.6%, 32.0% for whites and 18.4%, 50.5%, 30.9% for those of African descent), but there was a much higher frequency of the II genotype in those of South Asian origin (39.8%, 41.8%, 18.3%; chi2 = 77.6; P < 0.0001). There was no association between the I/D polymorphism and impaired glucose metabolism in any ethnic group. There were also no significant associations between the I/D polymorphism and hypertension in whites and in those of South Asian origin. This contrasts with a highly significant association between the D allele and hypertension in women of African descent (OR = 2.54; 95% CI 1.38-4.65; P = 0.003) but not in men of African descent (0.79; 0.36-1.72) (test for differences between sexes P = 0.023). CONCLUSIONS: These observations provide estimates of the frequency distribution of the ACE I/D polymorphism in whites, in people of African descent and in people of South Asian origin. Moreover, these results highlight the potential importance of gender-dependent interactions between genetic background and expression of hypertensive phenotype.

Adult↗
PubMed1999

Health effects of passive smoking-10: Summary of effects of parental smoking on the respiratory health of children and implications for research.

BACKGROUND: Two recent reviews have assessed the effect of parental smoking on respiratory disease in children. METHODS: The results of the systematic quantitative review published as a series in Thorax are summarised and brought up to date by considering papers appearing on Embase or Medline up to June 1998. The findings are compared with those of the review published recently by the Californian Environmental Protection Agency (EPA). Areas requiring further research are identified. RESULTS: Overall there is a very consistent picture with odds ratios for respiratory illnesses and symptoms and middle ear disease of between 1.2 and 1.6 for either parent smoking, the odds usually being higher in pre-school than in school aged children. For sudden infant death syndrome the odds ratio for maternal smoking is about 2. Significant effects from paternal smoking suggest a role for postnatal exposure to environmental tobacco smoke. Recent publications do not lead us to alter the conclusions of our earlier reviews. While essentially narrative rather than systematic and quantitative, the findings of the Californian EPA review are broadly similar. In addition they have reviewed studies of the effects of environmental tobacco smoke on children with cystic fibrosis and conclude from the limited evidence that there is a strong case for a relationship between parental smoking and admissions to hospital. They also review data from adults of the effects of acute exposure to environmental tobacco smoke under laboratory conditions which suggest acute effects on spirometric parameters rather than on bronchial hyperresponsiveness. It seems likely that such effects are also present in children. CONCLUSIONS: Substantial benefits to children would arise if parents stopped smoking after birth, even if the mother smoked during pregnancy. Policies need to be developed which reduce smoking amongst parents and protect infants and young children from exposure to environmental tobacco smoke. The weight of evidence is such that new prevalence studies are no longer justified. What are needed are studies which allow comparison of the effects of critical periods of exposure to cigarette smoke, particularly in utero, early infancy, and later childhood. Where longitudinal studies are carried out they should be analysed to look at the way in which changes in exposure are related to changes in outcome. Better still would be studies demonstrating reversibility of adverse effects, especially in asthmatic subjects or children with cystic fibrosis.

Adult↗
PubMed1999

Association between the C825T polymorphism of the G protein beta3-subunit gene and hypertension in blacks.

A polymorphism (C825T) of the G protein beta3-subunit gene has been associated with low renin hypertension in whites. The aim of this study was to examine the C825T polymorphism in relation to hypertension in a population-based study of black people of African origin who have high prevalence of low renin, salt-sensitive hypertension. A total of 428 men and women, aged 40 to 59 years (270 Caribbeans and 158 West Africans), who took part in a population-based survey were studied. All were blacks and first-generation immigrants. The C825T polymorphism was detected by polymerase chain reaction followed by restriction-enzyme digestion. The prevalence of hypertension (supine blood pressures >/=160 systolic and/or 95 mm Hg diastolic or on drug therapy) was 43%. The distribution of the genotypes (CC, CT, and TT) was in Hardy-Weinberg equilibrium with observed frequencies of 4.0% (n=17), 33.6% (n=144), and 62.4% (n=267), respectively. Allele frequencies were 20.8% for C and 79.2% for T. No difference was detected between Caribbeans and West Africans. A 3-fold higher risk of hypertension was found among the carriers of the T variant both as heterozygotes (odds ratio [OR], 3.43 [95% CI, 0.94 to 12.4]) and homozygotes (OR, 3.87 [95% CI, 1. 09 to 13.8]). The estimate of effect and the blood pressure values in the groups carrying the T variant suggested a dominant model for the T allele. This was confirmed by a significant association between the T allele and hypertension (OR, 3.71 [95% CI, 1.05 to 13. 1]), even when adjusted for age, sex, and body mass index (OR, 4.14 [95% CI, 1.11 to 15.4]). The study shows, for the first time, a high frequency of the 825T allele in black people, and it provides evidence that the T allele may be a susceptibility factor for the development of hypertension in blacks. Given the high frequency of the T allele, even a 2-fold increased risk of hypertension among the carriers of the T allele might account for 44% of the cases of hypertension in blacks.

Adult↗
PubMed1999

The effects of environmental tobacco smoke exposure on lung function in a longitudinal study of British adults.

Small effects of environmental tobacco smoke exposure on lung function have been demonstrated in many studies of children, but fewer studies have examined adults in this respect. We examined these relations in a 7-year longitudinal study of 1,623 British adults, age 18-73 years, who were nonsmokers throughout. Outcome was measured by forced expiratory volume in 1 second (FEV1) adjusted for sex, age, and height. Exposure was assessed by asking subjects whether they lived with a smoker (at both the initial and the follow-up studies) and by salivary cotinine measurements (follow-up study only). Cross-sectionally, subjects exposed at home showed tiny FEV1 deficits at both studies of -4 ml [95% confidence limits (CL) = -31, 23] and -5 ml (95% CL = -32, 22), respectively. Cotinine adjusted for potential confounders showed a stronger association with FEV1, with the highest quintile showing a -105-ml deficit (95% CL = -174, -37) in comparison with the lowest. Longitudinally, no clear relation was apparent between change in FEV1 and average exposure or change in exposure. These results indicate that environmental tobacco smoke is associated with small deficits in adult lung function, consistent with our meta-analysis estimate of a 2.7% deficit in exposed nonsmoking adults. The relations seen with cotinine but not with household exposure may reflect the importance of exposure outside the home.

Adolescent↗
PubMed1998

Association of hypertension with T594M mutation in beta subunit of epithelial sodium channels in black people resident in London.

BACKGROUND: Liddle's syndrome is a rare inherited form of hypertension in which mutations of the epithelial sodium channel result in increased renal sodium reabsorption. Essential hypertension in black patients also shows clinical features of sodium retention so we screened black people for the T594M mutation, the most commonly identified sodium-channel mutation. METHODS: In a case-control study, 206 hypertensive (mean age 48.0 [SD 11.8] years, men:women 80:126) and 142 normotensive (48.7 [7.4] years; 61:81) black people who lived in London, UK, were screened for T594M. Part of the last exon of the epithelial sodium-channel beta subunit from genomic DNA was amplified by PCR. The T594M variant was detected by single-strand conformational polymorphism analysis of PCR products and confirmed by DNA sequencing. FINDINGS: 17 (8.3%) of 206 hypertensive participants compared with three (2.1%) of 142 normotensive participants possessed the T594M variant (odds ratio [OR]=4.17 [95% CI 1.12-18.25], p=0.029). A high proportion of participants with the T594M variant were women (15 of 17 hypertensive participants and all three normotensive participants), whereas women comprised a lower proportion of the individuals screened (61.2% hypertensive, 57.7% normotensive). However, the association between the T594M variant and hypertension persisted after adjustment for sex and body-mass index (Mantel-Haenszel OR=5.52 [1.40-30.61], p=0.012). Plasma renin activity was significantly lower in 13 hypertensive participants with the T594M variant (median=0.19 ng mL(-1) h(-1)) than in 39 untreated hypertensive individuals without the variant (median=0.45 ng mL(-1) h(-1), p=0.009). INTERPRETATION: Among black London people the T594M sodium-channel beta subunit mutation occurs more frequently in people with hypertension than those without. The T594M variant may increase sodium-channel activity and could raise blood pressure in affected people by increasing renal tubular sodium reabsorption. These findings suggest that the T594M mutation could be the most common secondary cause of essential hypertension in black people identified to date.

Black People↗
PubMed1998

Maternal cotinine level during pregnancy and birthweight for gestational age.

BACKGROUND: Recent studies have found that cotinine is a better predictor of birthweight than the number of cigarettes smoked in pregnancy. In this paper we test this hypothesis and use cotinine to explore the effect of environmental tobacco smoke (ETS) on birthweight. METHODS: In all, 1254 white women were interviewed at booking, 28 and 36 weeks about the number and brand of cigarette smoked. Cotinine was assayed from blood samples taken on the day of interview. The outcome was birthweight for gestational age. RESULTS: There was good agreement between self-reported smoker/non-smoker status and maternal cotinine with 1.3% women mis-reported as non-smokers at booking, 0.6% and 1.8% mis-reported at 28 and 36 weeks respectively. Among smokers, cotinine was more closely related to birthweight than the number of cigarettes smoked at all three time points (r = -0.25 versus r = -0.16 at booking). A reduction in cotinine between booking and 28 weeks was associated with increased birthweight but the effect was not statistically significant. Among non-smokers the association between birthweight and cotinine was not statistically significant after adjusting for maternal height, parity, sex and gestational age. Difference in mean birthweight between non-smokers in the lower and upper quintiles of cotinine was 0.2% (95% CI: -2.4, 2.8). Pooling the results of 10 studies plus our own gave an estimated difference in mean birthweight between women unexposed and exposed to passive smoke of 31 g (95% CI: 19, 44). CONCLUSIONS: Cotinine is a better predictor of birthweight than the reported number of cigarettes smoked. If biochemical analysis is impossible, then self-reported smoking habit should be obtained prospectively using a structured approach. Any effect on birthweight of maternal passive smoking during pregnancy is small compared with the effects of maternal active smoking.

Adult↗