Yvonne Kelly

Breastfeeding and hospitalization for diarrheal and respiratory infection in the United Kingdom Millennium Cohort Study.

OBJECTIVE. The objective of this study was to measure the effect of breastfeeding on hospitalization for diarrheal and lower respiratory tract infections in the first 8 months after birth in contemporary United Kingdom. METHODS. The study was a population-based survey (sweep 1 of the United Kingdom Millennium Cohort Study). Data on infant feeding, infant health, and a range of confounding factors were available for 15890 healthy, singleton, term infants who were born in 2000–2002. The main outcome measures were parental report of hospitalization for diarrhea and lower respiratory tract infection in the first 8 months after birth. RESULTS. Seventy percent of infants were breastfed (ever), 34% received breast milk for at least 4 months, and 1.2% were exclusively breastfed for at least 6 months. By 8 months of age, 12% of infants had been hospitalized (1.1% for diarrhea and 3.2% for lower respiratory tract infection). Data analyzed by month of age, with adjustment for confounders, show that exclusive breastfeeding, compared with not breastfeeding, protects against hospitalization for diarrhea and lower respiratory tract infection. The effect of partial breastfeeding is weaker. Population-attributable fractions suggest that an estimated 53% of diarrhea hospitalizations could have been prevented each month by exclusive breastfeeding and 31% by partial breastfeeding. Similarly, 27% of lower respiratory tract infection hospitalizations could have been prevented each month by exclusive breastfeeding and 25% by partial breastfeeding. The protective effect of breastfeeding for these outcomes wears off soon after breastfeeding cessation. CONCLUSIONS. Breastfeeding, particularly when exclusive and prolonged, protects against severe morbidity in contemporary United Kingdom. A population-level increase in exclusive, prolonged breastfeeding would be of considerable potential benefit for public health.

Breastfeeding is Associated with Improved Child Cognitive Development: A Population-Based Cohort Study

OBJECTIVE To assess the association between breastfeeding and child cognitive development in term and preterm children. STUDY DESIGN We analyzed data on white singleton children from the United Kingdom Millennium Cohort Study. Children were grouped according to breastfeeding duration. Results were stratified by gestational age at birth: 37 to 42 weeks (term, n = 11,101), and 28 to 36 weeks (preterm, n = 778). British Ability Scales tests were administered at age 5 years (naming vocabulary, pattern construction, and picture similarities subscales). RESULTS The mean scores for all subscales increased with breastfeeding duration. After adjusting for confounders, there was a significant difference in mean score between children who were breastfed and children who were never breastfed: in term children, a two-point increase in score for picture similarities (when breastfed ≥ 4 months) and naming vocabulary (when breastfed ≥ 6 months); in preterm children, a 4-point increase for naming vocabulary (when breastfed ≥ 4 months) and picture similarities (when breastfed ≥ 2 months) and a 6-point increase for pattern construction (when breastfed ≥ 2 months). These differences suggest that breastfed children will be 1 to 6 months ahead of children who were never breastfed. CONCLUSIONS In white, singleton children in the United Kingdom, breastfeeding is associated with improved cognitive development, particularly in children born preterm.

Breastfeeding and Developmental Delay: Findings From the Millennium Cohort Study

OBJECTIVE. We investigated whether the duration and exclusivity of breastfeeding affects the likelihood of gross and fine motor delay in infants and examined the effect of factors that might explain any observed differences. METHODS. The study sample included all term singleton infants who weighed >2500 g at birth and were not placed in a special care infant unit and whose mothers participated in the first survey of the Millennium Cohort Study. Missing data reduced the sample to 14660 (94%) with complete data. RESULTS. Almost half (47%) of the infants initially were exclusively breastfed, but only 3.5% of these infants were still being fed exclusively on breast milk after 4 months of age, and 34% of infants were not breastfed at all; 9% of the infants were identified with delays in gross motor coordination and 6% with fine motor coordination delays at age 9 months. The proportion of infants who mastered the developmental milestones increased with duration and exclusivity of breastfeeding. Infants who had never been breastfed were 50% more likely to have gross motor coordination delays than infants who had been breastfed exclusively for at least 4 months (10.7% vs 7.3%). Any breast milk also was positively related to development: infants who had never been breastfed were 30% more likely to have gross motor delays than infants who were given some breast milk for up to 2 months (10.7% vs 8.4%). The odds ratios for gross motor delay were not attenuated after adjustment for biological, socioeconomic, or psychosocial factors. Infants who were never breastfed had at least a 40% greater likelihood of fine motor delay than infants who were given breast milk for a prolonged period. CONCLUSION. Our results suggest that the protective effect of breastfeeding on the attainment of gross motor milestones is attributable to some component(s) of breast milk or feature of breastfeeding and is not simply a product of advantaged social position, education, or parenting style, because control for these factors did not explain any of the observed association. In contrast, the association between breastfeeding and fine motor delay was explained by biological, socioeconomic, and psychosocial factors.

Breast-feeding initiation and exclusive duration at 6 months by social class--results from the Millennium Cohort Study.

OBJECTIVES To assess breast-feeding initiation and rates of exclusive breast-feeding for the first 6 months after birth, and to examine social class differences in breast-feeding rates. DESIGN First sweep of a longitudinal population-based survey, the Millennium Cohort Study. SETTING Four countries of the UK. SUBJECTS Subjects were 18 125 singletons born over a 12-month period spanning 2000-01. Data were collected by parental interview on the initiation of breast-feeding and exclusivity at 1, 4 and 6 months after birth. RESULTS Overall breast-feeding was initiated for 71% of babies, and by 1, 4 and 6 months of age the proportions being exclusively breast-fed were 34%, 3% and 0.3%, respectively. There were clear social class differences and mothers with routine jobs with the least favourable working conditions were more than four times less likely (odds ratio (OR) 0.22, 95% confidence interval (CI) 0.18-0.29) to initiate breast-feeding compared with women in higher managerial and professional occupations. Women in routine jobs were less likely to exclusively breast-feed their infants at 1 month (OR 0.42, 95% CI 0.36-0.50) and 4 months (OR 0.5, 95% CI 0.31-0.77) compared with women in higher managerial and professional occupations. CONCLUSIONS Clear social class differences in breast-feeding initiation and exclusivity for the first 4 months were apparent in this large UK sample. By 6 months, less than 1% of babies were being exclusively breast-fed. A co-ordinated multi-faceted strategy is required to promote breast-feeding, particularly among lower-income women.

Racial/Ethnic differences in breastfeeding initiation and continuation in the United Kingdom and comparison with findings in the United States?

OBJECTIVE. Patterns of breastfeeding vary considerably across different racial/ethnic groups; however, little is known about factors that might explain differences across and within different racial/ethnic groups. Here we examine patterns of breastfeeding initiation and continuation among a racially/ethnically diverse sample of new mothers and compare this with patterns seen in the United States. The effects of demographic, social, economic, and cultural factors on racial/ethnic differences in breastfeeding practices are assessed. METHODS. The sample includes all singleton infants whose mothers participated in the first survey of the United Kingdom Millennium Cohort Study. Missing data reduced the sample to 17474 (96%) infants with complete data. RESULTS. After adjustment for demographic, economic, and psychosocial factors, logistic regression models showed that Indian, Pakistani, Bangladeshi, black Caribbean, and black African mothers were more likely to initiate breastfeeding compared with white mothers. Further adjustment for a marker of cultural tradition attenuated these relationships, but all remained statistically significant, suggesting that some of the difference was a consequence of cultural factors. After adjustment for demographic, economic, and psychosocial factors, Indian, Pakistani, Bangladeshi, black Carribbean, and black African mothers were more likely to continue breastfeeding at 3 months compared with white mothers. Additional adjustment for a marker of cultural tradition attenuated the relationship for Indian, Pakistani, Bangladeshi, and black African mothers, but all remained statistically significant. Models run for breastfeeding continuation at 4 and 6 months were consistent with these results. CONCLUSIONS. We have shown that in the United Kingdom the highest breastfeeding rates are among black and Asian mothers, which is in stark contrast to patterns in the United States, where the lowest rate is seen among non-Hispanic black mothers. The contrasting racial/ethnic patterns of breastfeeding in the UnitedKingdom and United States necessitate very different public health approaches to reach national targets on breastfeeding and reduce health disparities. Those who implement future policies aimed at increasing breastfeeding rates need to pay attention to different social, economic, and cultural profiles of all racial/ethnic groups.

Why does birthweight vary among ethnic groups in the UK? Findings from the Millennium Cohort Study

BACKGROUND Birthweight varies according to ethnic group, but it is not clear why such differences exist. We examine the contribution of socioeconomic, maternal and behavioural factors to differences in mean birthweight and the prevalence of low birthweight across ethnic groups. METHODS Data from the nationally representative UK Millennium Cohort Study (n = 16,157) on White, Indian, Pakistani, Bangladeshi, Black Caribbean and Black African infants were analysed. Cohort members were born in 2000-02, and data on birthweight, maternal, infant, behavioural and socioeconomic factors were collected by home interviews. RESULTS Indian, Pakistani and Bangladeshi infants were 280-350 g lighter, and 2.5 times more likely to be low birthweight compared with White infants. Black Caribbean infants were 150 g and Black African infants 70 g lighter compared with White infants, and Black Caribbean and Black African infants were 60% more likely to be low birthweight compared with White infants. For Black Caribbean, Black African, Bangladeshi and Pakistani infants, socioeconomic factors were important in explaining birthweight differences and, for Indian and Bangladeshi infants, maternal and infant factors were important in explaining birthweight differences. CONCLUSION Future policies aimed at reducing inequalities in birthweight must pay attention to the different socioeconomic and culturally-related profiles of ethnic minority groups in the UK.

Nutrition and respiratory health in adults: findings from the Health Survey for Scotland

There is a growing body of evidence to support the hypothesised links between consumption of antioxidant rich foods and the occurrence of obstructive airway disease. The main research question was to examine the relationships between two types of dietary exposure and two indicators of respiratory morbidity in Scottish adults. The relationships between dietary consumption of fruit, vegetables and fish, and plasma levels of vitamins A, C, E and β-carotene, and pulmonary function (forced expiratory volume in one second (FEV1)) and symptoms (phlegm production and shortness of breath with wheezing), were examined in a random population sample of adults. A dose/response relationship was found between fruit consumption and pulmonary function. In comparison with eating fruit rarely or never, eating fruit at least once per day, 1–6 times per week, and 1–3 times per month were associated with differences of 132, 100 and 63 mL in FEV1, after adjustment for known confounders and dietary intake of vegetables and fish (n=6186). An sd score change in plasma vitamin C was associated with a 49 mL difference in FEV1 (n=930). Fruit and vitamin E were associated with a reduced prevalence of phlegm production for 3 months or more per year. The most beneficial combination of dietary components may be found in natural foodstuffs, particularly fresh fruit.

Ethnic differences in achievement of developmental milestones by 9 months of age: the Millennium Cohort Study

This paper examines ethnic differences in the attainment of developmental milestones during infancy and possible explanations for observed differences are investigated. Data from the first survey of the Millennium Cohort Study (n = 15,994; 8212 males, 7782 females; mean age 9.2 mo [SD 0.5]) were examined. We found that Black Caribbean (odds ratio [OR] = 0.23, 95% confidence interval [CI] = 0.11-0.48), Black African (OR 0.31, 95% CI 0.18-0.55), and Indian (OR 0.55, 95% CI 0.33-0.93) infants were less likely to show delay in the attainment of gross motor milestones compared with White infants after adjustment for a range of explanatory variables. Pakistani and Bangladeshi infants were more likely to have delays in fine motor development (OR 1.69, 95% CI 1.21-2.35 and OR 2.17, 95% CI 1.17-4.02 respectively) and communicative gestures (OR 4.19, 95% CI 1.47-11.94 and OR 7.64, 95% CI 3.96-14.76 respectively), but these differences were explained by socioeconomic factors and markers of cultural tradition. In conclusion, unexplained ethnic differences were seen in the attainment of gross motor milestones, with Indian, Black Caribbean, and Black African children less likely to be delayed (in adjusted models). Increased likelihood of fine motor and communicative gesture delays among Pakistani and Bangladeshi infants, that disappear when socioeconomic factors are taken into account, point to the need to address deprivation among these groups to reduce the likelihood of developmental delay and possible longer term behavioural and cognitive problems and consequent opportunities throughout life.

Breast feeding and child behaviour in the Millennium Cohort Study

Objective To examine whether breast feeding is associated with behavioural development in children aged 5 years. Design The authors used data from a large, prospective, nationally representative UK cohort, the Millennium Cohort Study. Participants 10 037 mother–child pairs from white ethnic background (9525 term and 512 preterm children) were included in the analyses. Methods Duration of breast feeding (at all or exclusively) was ascertained from parental interview at study baseline, when the children were aged 9 months. Child behaviour was assessed using a parent-completed questionnaire, the Strengths and Difficulties Questionnaire (SDQ). The authors used logistic regression to investigate the associations of breastfeeding duration with abnormal parent-rated SDQ total and subscores at age 5 in term and preterm children separately. Results Abnormal SDQ scores were less common in term children (n=1129/9525, 12%) than pre-term (n=78/512, 15%) children. Term children breast fed for 4 months or longer (n=2741/9525, 29%) had lower odds of an abnormal total SDQ score (multivariable-adjusted OR compared with never breastfed children (n=3292/9525, 35%) 0.67, 95% CI: 0.54 to 0.83). This effect was similar for all the SDQ subscores. In preterm children, longer duration of breast feeding was generally associated with lower odds of abnormal SDQ total and subscores but the effect estimates were imprecise. The associations between exclusive breast feeding and abnormal SDQ scores were similar to those of any breast feeding and abnormal SDQ scores. Conclusions The findings suggest that, at least in term children, longer duration of breast feeding is associated with fewer parent-rated behavioural problems in children aged 5 years.

Life course epidemiology: recognising the importance of adolescence

Life course epidemiology may be conceptualised as “the study of long term effects on later health or disease risk of physical or social exposures during gestation, childhood, adolescence, young adulthood and later adult life.”1 Adolescence, the period between childhood and adulthood defined by the WHO as 10–19 years, has an uneasy status in epidemiology. On the one hand, adolescents, who now number over 1.2 billion worldwide—around 20% of the global population—are highly visible in population-based studies. Young peoples behaviours have been an important subject of epidemiological inquiry, from tobacco and alcohol use to violence and sexual activity. Yet, concepts of adolescence as a discrete stage in the life course have been much less discussed within epidemiology. This is particularly so in studies of the developmental origins of adult health and disease, which have focused on the influence on adult health outcomes of exposures from the period of rapid physiological change in very early life. Similarly, investigators in the field of the social determinants of health and disease have concentrated their efforts on the effects of parenting and education in early childhood. With the aim of developing our understanding of the place of adolescence in a life course framework, in May 2013, we organised a joint workshop between UCL and the London School of Hygiene and Tropical Medicine. Studies of the biological embedding of early life experiences have focused largely on prenatal or infant life, and have led to the understanding that periods of rapid organ system development during these phases of life are critical to adult health.1 Yet, adolescence is second only to fetal and infant life …