Is breastfeeding beneficial and maternal smoking harmful to the cognitive development of children?

The effects of breastfeeding on cognitive, visuomotor and language development were examined in healthy children born at full term, after they had reached 56 months of age. Three hundred and sixty-three children were breastfed for less than 5 months, and 363 for 5 months or more. The groups were matched pairwise having regard to maternal education and sex of the child. Significant differences were found in relation to scores reflecting general cognitive capacity, and the results of the visuomotor integration test between children breastfed for less than 5 months and those breastfed for 5 months or more, and between children of mothers who had smoked during pregnancy and non-smoking mothers. In multiple linear regression analysis prolonged breastfeeding was significantly related to scores reflecting general cognitive capacity and results of the visuomotor integration test. However, smoking by mothers during pregnancy was not significantly related to scores in cognitive tests. Biological factors, and factors such as lifestyle and social background, may be more important determinants of a child's development than breastfeeding.     

Maternal cigarette smoking and breastfeeding duration

AIM: To examine the relationship between cigarette smoking and breastfeeding duration at 2 wk, 6 mo, and longer. METHODS: Design. A 12-mo longitudinal study. Setting. Two public maternity hospitals in the Perth metropolitan area (Western Australia). Subjects. Eligible mothers of healthy newborn infants. Interventions. Participants completed a self-administered baseline questionnaire while in hospital or shortly after discharge. All women regardless of their chosen infant feeding method were followed up by telephone interview at 4, 10, 16, 22, 32, 40 and 52 wk postpartum. Main outcome measures. Prevalence of breastfeeding at 2 wk, 2 wk to 6 mo and >6 mo in women who smoked during pregnancy, and breastfeeding duration. RESULTS: Women who smoked during pregnancy had a lower prevalence and shorter duration of breastfeeding than non-smoking mothers (28 vs 11 wk, 95% CI 8.3-13.7). This effect remained even after adjustment for age, education, income, father's smoking status, mother's country of birth, intended duration of breastfeeding >6 mo and birthweight (risk ratio 1.59, 95% CI 1.22-2.08). CONCLUSION: Women who smoke during pregnancy are at greater risk of not achieving national and international targets for breastfeeding. Encouraging smoking cessation in the antenatal setting is an area for considerable public health gain.     

Effects of parental smoking and level of education on initiation and duration of breastfeeding

Aim: To evaluate the effects of parental smoking and level of education on the initiation and duration of breastfeeding in a prospective cohort study on mother-infant pairs. Methods: We studied 543 mother-infant pairs enrolled after delivery at a hospital in Rome. Information about parents' characteristics were obtained from a questionnaire administered in hospital; the outcome of the study was the infant's feeding habits in the preceding 24 h, assessed by telephone every 2 wk. The effects of parental smoking and level of education on initiation and duration of breastfeeding were evaluated through multivariate logistic regression models and time-dependent Cox models. Results: After controlling for confounding factors, we found a negative effect for mothers' smoking both on breastfeeding initiation (odds ratio 2.19, 95% CI 1.05-4.55) and duration (hazard ratio 3.37, 95% CI 1.85-6.13) when at least one parent had a low level of education.

Conclusion: Our study shows that maternal smoking, particularly when one of the parents has a low level of education, determines a negative effect on the initiation and duration of breastfeeding. Public health policy should promote educational programmes for both parents focused on quitting smoking, which could have positive effects on the initiation and duration of breastfeeding.     

Impact of smoking on the duration of breastfeeding in mothers with insulin-dependent diabetes mellitus

The effect of smoking on breastfeeding was studied in 252 mothers with insulin-dependent diabetes mellitus (IDDM) giving birth in the period 1985-1995 and of whom 31% were classified as White group B, 16% group C, 37% group D and 16% group F or R. As part of a centralized regimen a detailed smoking history was taken during pregnancy. Forty-six percent were smokers. In 1997, a questionnaire was sent out asking for information on the duration of breastfeeding. The response rate was 87%. The duration of breastfeeding was significantly longer in the non-smoking group (p = 0.004). Fifty-five percent of non-smokers versus 33% of smokers were still breastfeeding 4 mo after birth. A strong dose-response relationship was established (p = 0.009). Cox multiple regression analysis showed a significantly negative influence of smoking (p = 0.01) and of hospitalization of the infants during the first year of life (p = 0.02) and a significantly positive influence of maternal age (p = 0.02) and birthweight (p = 0.03) on the length of breastfeeding. The breastfeeding curves for non-smokers and smokers were mainly divergent in the first month after birth, suggesting that the effect of smoking on breastfeeding is mainly exerted during that period. CONCLUSION: Smoking exerted a strong, negative, dose-dependent influence on breastfeeding duration in mothers with IDDM. Given the hazards of smoking, the advantages of breastfeeding and the possible link between being breastfed and later development of diabetes mellitus, these results should be taken into consideration when counselling pregnant women with IDDM about smoking.     

The relationship between maternal smoking and breastfeeding duration after adjustment for maternal infant feeding intention

AIM: To investigate whether maternal smoking remains associated with decreased breastfeeding duration after adjustment for the mother's infant feeding intention. METHOD: Pregnant women resident within Avon, UK, expected to give birth between 1 April 1991 and 31 December 1992 were recruited in a longitudinal cohort study. Main outcome measures included maternal infant feeding intention at 32 wk of pregnancy: intention for the first week, intention for the rest of the first month and intention in months 2 to 4. Maternal smoking was defined as any smoking reported at any time during pregnancy. Data on initiation and duration of breastfeeding were based on the questionnaire at 6 mo postpartum, supplemented by data from the 15-mo questionnaire if necessary. RESULTS: Women who smoked during pregnancy had an adjusted odds ratio of 1.5 (95% CI: 1.3-1.7) of not breastfeeding at 6 mo compared to non-smokers (adjusting for maternal age, education and intention). Survival analysis of duration of breastfeeding in the first 6 mo postpartum found that women who intended to breastfeed for less than 1 mo were 78% more likely to stop at any given time than women planning to breastfeed for at least 4 mo, while smokers were 17% more likely to stop breastfeeding than non-smokers. CONCLUSION: Although women who smoke are less likely to breastfeed their infants than are non-smoking women, it appears that this is largely due to lower motivation to breastfeed rather than a physiological effect of smoking on their milk supply.     

Sleeping position, breastfeeding, bedsharing and passive smoking in 3-month-old Swedish infants

Parents of 1028 infants who attended community-based infant health clinics were interviewed concerning infant sleeping position, feeding habits, bedsharing and passive smoking at 3 months of postnatal age. In addition, they were asked to state which source of information had mainly influenced them in the choice of the sleeping position. Fifteen per cent of the infants were regularly laid to sleep in the prone position, compared with 72% (1991) before official guidelines concerning infant sleeping position were issued. The overall prevalence of exclusive breastfeeding was 70.4%. Prevalence of maternal smoking was 17.9% and 22.8% of the infants were regularly bedsharing with the parents. Those mothers who did not comply with official recommendations regarding infant sleeping position were also less likely to follow other recommendations concerning infant care practices. Prone sleeping infants were more likely to be formula fed and exposed to passive smoking, and hence associated with additional risk factors for sudden infant death syndrome.     

Factors associated with the duration of breastfeeding amongst women in Perth, Australia

Duration of breastfeeding was studied in 556 women delivering at 2 maternity hospitals in Perth, Australia. At discharge 83.8% of women were breastfeeding their infants, including 6% who were giving complementary feeds. At 3 and 6 months, 61.8% and 49.9%, respectively, were still breastfeeding. In a Cox survival analysis of factors associated with duration of breastfeeding a positive association was found with maternal education, age and intended duration of breastfeeding. Male infants were more likely to be weaned before female infants and women whose partners were unemployed, or did not have a preference for breastfeeding, breastfed for shorter duration. There is still a need for programmes which support and encourage breastfeeding, focusing particularly on younger, less well-educated women who intend to breastfeed for less than the recommended 4-6 months.     

Differential trends in breastfeeding according to maternal and hospital characteristics: results from the French National Perinatal Surveys

AIM: To assess breastfeeding trends in hospital, between 1998 and 2003, according to several characteristics of mothers and maternity units. METHODS: Two representative national samples of births, comprising 13,600 live births in 1998 and 14,580 in 2003 were used. Data were collected during hospital stay. All newborns fed entirely or partly on breast milk were considered 'breastfed'. Univariate and multivariate analyses were used to compare the results for the 2 years. RESULTS: Breastfeeding increased in all groups, but this increase varied slightly according to maternal age and the size of the maternity unit. For example, high rates of breastfeeding tended to be concentrated in large maternity units (> or = 1500 deliveries per year) in 1998, but were also found in middle-size units (1000-1499 deliveries per year) in 2003. In 2003, women were more likely to breastfeed if they were at least 25 years old, primiparous, non-French or from a highly qualified occupational group, or if they gave birth in a university hospital or in a maternity unit with more than 1000 deliveries per year. CONCLUSION: Despite recent efforts to increase the breastfeeding rate, clear social disparities persist and further efforts are required, targeting particular groups of mothers less likely to breastfeed.     

Changes in parental risk behaviour after an information campaign against sudden infant death syndrome (SIDS) in Norway

AIM: To assess parental risk behaviour before and after a sudden infant death syndrome (SIDS) information campaign with special emphasis on associations with maternal age, education, marital status and birth order. METHODS: Data from questionnaires sent to all mothers who gave birth in Norway during a period before the campaign were compared with corresponding data obtained after the campaign. RESULTS: Prevalence of non-supine sleeping position decreased from 33.7% to 13.6% while changes in smoking, non-breastfeeding and co-sleeping were disappointing. Risk factors were particularly prevalent in young mothers, but also in mothers with a minimum period of education, non-cohabitation and at birth order 2+. CONCLUSIONS: Non-supine sleeping decreased to a level that has never been reported before. In future campaigns, subgroup-specific measures may be needed.     

Initiation of breastfeeding

Breastfeeding is a biological process that is highly influenced by various physiological and environmental factors such as the plans for infant feeding of pregnant women, their education and work situation, family support and nutrition.
Conclusion : The way in which breastfeeding is initiated in the early postnatal period is of importance both for how long the process is likely to continue and for the growth of the infant.     

Secular trends in newborn sex ratios

A wide variety of factors have been shown to influence the male to female ratio at birth, which invariably displays a male excess. This paper will review and amplify recent work by the author, with specific references to individual countries, regions and entire continents in order to provide a global overview of this subject. It will be shown that stress, including stress related to political events, influences this ratio. Man-made radiation is also shown to have played a significant role in relation to the Windscale fire (1957) and Chernobyl (1986).     

Breastfeeding, smoking and the presence of the child's father in the household

The breastfeeding practice of 312 mothers attending mother and child health centres in Oslo, Norway, was measured using self-administered questionnaires. Having started with supplements at 3 months postpartum was related to having a spouse/cohabitant, smoking, and having only one child (logistic-regression with civil state, age, education, smoking, number of children, social support, smoking × civil state, and education × civil state as independent variables). The frequency of having started with supplements increased with increasing maternal cigarette consumption. Among non-smoking, married/cohabiting mothers, the frequency of having started with supplements at 3 months postpartum was 41% if the spouse/cohabitant smoked, compared with 18% if he did not smoke ( p < 0.01).     

Secular Trends of Sudden Infant Death Syndrome and Other Causes of Post Perinatal Mortality in Norwegian Birth Cohorts 1967–1984

ABSTRACT. Lack of positive diagnostic criteria and increasing professional concern, probably causing increasing ascertainment, have rendered reported increases in SIDS-rates controversial. However, these problems related to cause specific mortality do not apply to the total mortality. Due to the exceptional age-at-death distribution of SIDS cases, the SIDS fraction of all deaths increases during the first year of life to reach a maximum, in the present study of 56%, from the 105th through the 125th day of life. During these days, the total mortality rate in Norway increased from 0.24 per 1000 in 1971–72 to 0.46 in 1983–84. Thus, the observed trend, with an increase in the SIDS rate from 1.02 per 1000 in 1971–72 to 2.34 in 1983–84, is considered true. Observed in a country where perinatal and neonatal mortality have decreased for a long period of time and still remain very low in a global perspective, the increasing SIDS rate is a matter of great concern.     

Ten-year trends in obesity among Israeli schoolchildren: 1990-2000

AIM: To analyze trends in childhood body mass index (BMI) in Israel between 1990 and 2000, and to determine the proportion of obese children using US and population-specific reference values. METHODS: Cross-sectional data from 13 284 second- and fifth-grade schoolchildren were collected, including age, sex, height, weight, country of birth, and time since immigration. Age- and sex-specific BMI means and centiles were calculated, and the prevalence of obesity was determined using Israeli and US reference values. RESULTS: BMI values at the 95th centile increased monotonously over time in all age and sex categories. Between 1990 and 2000, 95th centile values increased by 12.7% and 11.8% among second-grade boys and girls, respectively. Among fifth-grade children, 95th centile values increased by 10.2% and 8.4%, respectively. Among second graders in 2000, 11.4% of both boys and girls exceeded the BMI value recorded at the 95th centile in 1990. Among fifth-graders in 2000, 10.7% of boys and 11.1% of girls exceeded the 1990 BMI reference value (p for all comparisons < 0.001). The proportion of obese children increased over time using both Israeli and US reference values. CONCLUSION: This substantial increase in childhood obesity poses a serious health threat, and requires implementation of suitable public health interventions.     

Down syndrome and breastfeeding

AIM: The aim of the study was to investigate the frequency of breastfeeding among children with Down syndrome. METHODS: The mothers of 560 children with Down syndrome attending four university hospitals in Italy were interviewed and the neonatal clinical records retrieved. Information was collected on the type of infant feeding and on why some mothers had not breastfed their children. Two groups of healthy children whose feeding habits had been previously investigated were recruited as control subjects (1601 and 714, respectively). A paediatrician in each hospital was interviewed about the neonatal admission policy of children with Down syndrome. RESULTS: Among the 560 Down children, 246 (44%) were admitted to the neonatal unit. Compared with the two control groups, children with Down syndrome were significantly more frequently bottle-fed (57% vs 15% and 24%, respectively, odds ratio 7.5, 95% CI 6.0-9.4 and 4.2, 95% CI 3.3-5.4. respectively). Only 30% of infants admitted to the neonatal unit were breastfed. The main reasons reported by the mothers for not having breastfed were infants' illness in infants who had been admitted to the neonatal unit and frustration or depression, perceived milk insufficiency and difficulty with suckling for those babies who had not been admitted to the unit. The paediatricians reported that the admission of a baby with Down syndrome to the neonatal unit could sometimes take place not for medical reasons, but for diagnostic work-up or for a more appropriate diagnosis and to maintain communication with the family. CONCLUSIONS: Down syndrome babies are less frequently breastfed compared with healthy children. Support in breastfeeding should become a relevant point of health supervision for children with Down syndrome.     

Prenatal and postnatal parental smoking and acute otitis media in early childhood

Aim:  To explore the associations between acute otitis media in early childhood and prenatal and postnatal tobacco smoke exposure.
Methods:  Subjects were 32 077 children born between 2000 and 2005 in the Norwegian Mother and Child Study with questionnaire data on tobacco smoke exposure and acute otitis media up to 18 months of age. Multivariate regression models were used to obtain adjusted relative risks for acute otitis media.
Results:  Acute otitis media was slightly more common in children exposed to parental smoking. The incidence from 0 to 6 months was 4.7% in unexposed children and 6.0% in children exposed both prenatally and postnatally. After adjusting for postnatal exposure and covariates, the relative risk for acute otitis media 0–6 months when exposed to maternal smoking in pregnancy was 1.34, 95% confidence interval: 1.06–1.69. Maternal smoking in pregnancy was associated with acute otitis media up to 12 months of age. Compared with non-exposed children, there was a slightly increased risk of recurrent acute otitis media for children exposed both prenatally and postnatally with a relative risk of 1.24, 95% confidence interval: 1.01–1.52.
Conclusion:  Even in a cohort with relatively low exposure levels of parental smoking, maternal smoking in pregnancy was associated with an increased risk of acute otitis media in early childhood.