Wendy H. Oddy

Predictors of Breastfeeding Duration: Evidence From a Cohort Study

OBJECTIVE. To report the duration of breastfeeding among a population of Australian women and to identify factors that are associated with the duration of full breastfeeding to 6 months and any breastfeeding to 12 months. METHODS. Participants were 587 women who were recruited from 2 maternity hospitals in Perth and completed a baseline questionnaire just before or shortly after discharge from the hospital. Women were followed up by telephone interview at 4, 10, 16, 22, 32, 40, and 52 weeks postpartum. Data collected included sociodemographic, biomedical, hospital-related, and psychosocial factors associated with the initiation and the duration of breastfeeding. Coxs proportional hazards model was used to identify factors that were associated with the risk for discontinuing full breastfeeding before 6 months and any breastfeeding before 12 months. RESULTS. At 6 months of age, fewer than one half of infants were receiving any breast milk (45.9%), and only 12% were being fully breastfed. By 12 months, only 19.2% of infants were still receiving any breast milk. Breastfeeding duration was independently, positively associated with maternal infant feeding attitudes and negatively associated with breastfeeding difficulties in the first 4 weeks, maternal smoking, introduction of a pacifier, and early return to work. CONCLUSIONS. Relatively few women achieved the international recommendations for duration of full and overall breastfeeding. Women should receive anticipatory guidance while still in the hospital on how to prevent or manage common breastfeeding difficulties and should be discouraged from introducing a pacifier before 10 weeks, if at all. Improved maternity leave provisions and more flexible working conditions may help women to remain at home with their infants longer and/or to combine successfully breastfeeding with employment outside the home.

The effects of respiratory infections, atopy, and breastfeeding on childhood asthma

The objectives of the present study were to quantify the association of atopy and respiratory infections with asthma, and exclusive breastfeeding with respiratory illness, atopy and asthma in children. A cohort study of 2,602 children enrolled prior to birth and followed prospectively, provided data on respiratory illness, the method of feeding in the first year of life, as reported on a prospective diary card, and current asthma at the age of 6 yrs (defined as doctor-diagnosed asthma with wheeze in the last year or cough without a cold, and currently taking either preventer or reliever asthma medication), as reported by parental questionnaire. Atopy was defined by a positive skin-prick test assessed at the age of 6 yrs. Wheezing lower respiratory illness (LRI) in the first year of life, particularly multiple episodes of wheezing LRI, increased the risk for current asthma in both nonatopic (odds ratio (OR) 4.10, p⪕0.0005) and atopic children (OR 9.00, p⪕0.0005), but did not increase the risk for atopy. In contrast, up to three upper respiratory tract infections demonstrated a negative association and four or more a positive risk for current asthma in unadjusted (p=0.006) and adjusted (p=0.057) analysis. Following adjustment, exclusive breastfeeding for <4 months was associated with an increased risk for current asthma (OR 1.36, 95% confidence interval 1.00–1.85, p=0.047). Wheezing lower respiratory illness in the first year of life and atopy are independently associated with increased risk for current asthma at the age of 6 yrs, suggesting that their effects are mediated via different causal pathways and that these risk factors are multiplicative when they operate concomitantly within individual children. Exclusive breastfeeding protects against asthma via effects on both these pathways, as well as through other as yet undefined mechanisms.

Predictors of body mass index and associations with cardiovascular risk factors in Australian children: a prospective cohort study

OBJECTIVE:To examine predictors of body mass index (BMI) at the age of 8 y in a prospective study of Australian children.DESIGN:Longitudinal survey of a cohort of Australian children followed from the 16th week of gestation to 8 y.SUBJECTS:In total, 741 boys and 689 girls who attended the survey as 8 y olds.MEASUREMENTS:Weight and height, blood pressure measured by automated oscillometry, fasting blood lipids and glucose. Questionnaire assessment of activity and diet.RESULTS:Proportions of overweight including obesity in boys and girls were, respectively, 22 and 25% at 1 y, 14 and 14% at 3 y, 13 and 18% at 5 y and 15 and 20% at 8 y. At the age of 1, 3, 6 and 8 y, children with overweight including obesity showed significantly more adverse cardiovascular risk factors. Blood pressure (BP) was significantly higher by 2/3 mmHg (systolic/diastolic) at 1 y, 3/2 mmHg at 3 y, 4/2 mmHg at 5 y and 6/2 mmHg at 8 y; HDL was significantly lower (P=0.002) by 8% and triglycerides were significantly higher by 27% (P<0.001). In multivariate regression, BMI at the age of 8 y was significantly predicted positively by birth weight, mothers BMI and hours spent in watching television at the time of the survey of 6 y olds. Mothers being ex-smokers or non smokers and children being ‘slightly active’ and ‘active’ negatively predicted BMI in 8 y olds. In a subset of 298 children with information about fathers, paternal BMI was an additional independent predictor. Maternal or paternal overweight including obesity each independently increased risk of overweight including obesity at the age of 8 y three-fold. A food factor with consumption of cereals and breads as the major components derived from a Food Frequency Questionnaire in a subset of 340 children was also an independent negative predictor of BMI in multivariate models.CONCLUSION:The increasing rate of overweight including obesity, particularly in girls, is associated with an increase in cardiovascular risk factors very early in life. Improvement of health-related behaviours within the family and a focus on promotion of activity in children should be priorities in achieving weight control.

The role of nutrition in children's neurocognitive development, from pregnancy through childhood

This review examines the current evidence for a possible connection between nutritional intake (including micronutrients and whole diet) and neurocognitive development in childhood. Earlier studies which have investigated the association between nutrition and cognitive development have focused on individual micronutrients, including omega-3 fatty acids, vitamin B12, folic acid, choline, iron, iodine, and zinc, and single aspects of diet. The research evidence from observational studies suggests that micronutrients may play an important role in the cognitive development of children. However, the results of intervention trials utilizing single micronutrients are inconclusive. More generally, there is evidence that malnutrition can impair cognitive development, whilst breastfeeding appears to be beneficial for cognition. Eating breakfast is also beneficial for cognition. In contrast, there is currently inconclusive evidence regarding the association between obesity and cognition. Since individuals consume combinations of foods, more recently researchers have become interested in the cognitive impact of diet as a composite measure. Only a few studies to date have investigated the associations between dietary patterns and cognitive development. In future research, more well designed intervention trials are needed, with special consideration given to the interactive effects of nutrients.

The association between dietary patterns and mental health in early adolescence

OBJECTIVE To investigate the associations between dietary patterns and mental health in early adolescence. METHOD The Western Australian Pregnancy Cohort (Raine) Study is a prospective study of 2900 pregnancies recruited from 1989-1992. At 14 years of age (2003-2006; n=1324), the Child Behaviour Checklist (CBCL) was used to assess behaviour (characterising mental health status), with higher scores representing poorer behaviour. Two dietary patterns (Western and Healthy) were identified using factor analysis and food group intakes estimated by a 212-item food frequency questionnaire. Relationships between dietary patterns, food group intakes and behaviour were examined using general linear modelling following adjustment for potential confounding factors at age 14: total energy intake, body mass index, physical activity, screen use, family structure, income and functioning, gender and maternal education at pregnancy. RESULTS Higher total (b=2.20, 95% CI=1.06, 3.35), internalizing (withdrawn/depressed) (b=1.25, 95% CI=0.15, 2.35) and externalizing (delinquent/aggressive) (b=2.60, 95% CI=1.51, 3.68) CBCL scores were significantly associated with the Western dietary pattern, with increased intakes of takeaway foods, confectionary and red meat. Improved behavioural scores were significantly associated with higher intakes of leafy green vegetables and fresh fruit (components of the Healthy pattern). CONCLUSION These findings implicate a Western dietary pattern in poorer behavioural outcomes for adolescents. Better behavioural outcomes were associated with a higher intake of fresh fruit and leafy green vegetables.

Low–moderate prenatal alcohol exposure and risk to child behavioural development: a prospective cohort study

Please cite this paper as: Robinson M, Oddy W, McLean N, Jacoby P, Pennell CE, de Klerk N, Zubrick S, Stanley F, Newnham J. Low–moderate prenatal alcohol exposure and risk to child behavioural development: a prospective cohort study. BJOG 2010;117:1139–1152.

TGF-β in human milk is associated with wheeze in infancy

Abstract Background Cytokines secreted in human milk might play important roles in newborn health and in the development of infant immune responses. We investigated the relationship of the concentration and dose of cytokines in human milk to infant wheeze at 1 year of age. Objective Our objective was to test whether the cytokines in milk could account for some of the apparent protective effect of breast-feeding against wheeze in the first year of life. Methods Data on breast-feeding and infant wheeze were collected prospectively from birth to 1 year from 243 mothers participating in the Infant Immune Study in Tucson, Arizona. Breast milk samples obtained at a mean age of 11 days postpartum were assayed by means of ELISA for concentrations of TGF-β1, IL-10, TNF-α, and the soluble form of CD14. The dose of each cytokine was assessed for a relationship with wheeze in bivariate and logistic regression analyses. Results Increasing duration of breast-feeding was significantly associated with a decreased prevalence of wheeze ( P = .039). There was wide variability in levels of each cytokine in milk, as well as variability between women in the amount of each cytokine produced. There was a significant inverse association between the dose of TGF-β1 received through milk with the percentage of wheeze ( P = .017), and the relationship was linear ( P = .006). None of the other cytokines showed a linear relationship with wheeze. In multivariate analyses the risk of wheeze was significantly decreased (odds ratio, 0.22; 95% CI 0.05-0.89; P = .034) with increasing TGF-β1 dose (long breast-feeding and medium-high TGF-β1 level compared with short breast-feeding and low TGF-β. Conclusion This analysis shows that the dose of TGF-β1 received from milk has a significant relationship with infant wheeze, which might account for at least some of the protective effect of breast-feeding against wheeze.

Gender-Specific Differences in Adipose Distribution and Adipocytokines Influence Adolescent Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a predominantly adult‐diagnosed disorder. Knowledge regarding the epidemiology, phenotype, and metabolic risk factors, during adolescence is limited. We sought to determine the prevalence, phenotype, and predictors of NAFLD in 1170 community‐based adolescents in the Western Australian Pregnancy Cohort (Raine) Study (the Raine Cohort) who underwent a cross‐sectional assessment that included questionnaires, anthropometry, cardiovascular examinations, blood tests, and abdominal ultrasound examinations. Among the 1170 adolescents assessed, the prevalence of NAFLD was 12.8%. Females compared with males had a significantly higher prevalence of NAFLD (16.3% versus 10.1%, P = 0.004) and central obesity (33.2% versus 9.9%, P < 0.05). The severity of hepatic steatosis was associated with the body mass index, waist circumference, subcutaneous adipose tissue thickness (SAT), serum leptin level, homeostasis model assessment for insulin resistance score (P < 0.001 for all), and serum alanine aminotransferase level (P < 0.005) in both genders, but it was associated with increasing visceral adipose tissue thickness (VAT; P < 0.001) and decreasing serum adiponectin levels (P < 0.05) in males alone. Males and females with NAFLD had similar amounts of SAT (P > 0.05); however, in comparison with females with NAFLD, males with NAFLD had greater VAT, a more severe metabolic phenotype with higher glucose levels and systolic blood pressure and lower adiponectin and high‐density lipoprotein cholesterol levels (P < 0.001 for all), and greater measures of liver injury (alanine aminotransferase and aspartate aminotransferase, P < 0.001 for all). Similarly, metabolic syndrome was more common in males than females with NAFLD (24% versus 8%, P = 0.01). Suprailiac skinfold thickness predicted NAFLD independently of the body mass index, insulin resistance, and VAT. Conclusion: Gender differences in adolescent NAFLD are related to differences in adipose distribution and adipocytokines. The male phenotype of NAFLD is associated with more adverse metabolic features and greater visceral adiposity than the female phenotype despite the lower prevalence of NAFLD. (HEPATOLOGY 2011;)

The relation of breastfeeding and body mass index to asthma and atopy in children: A prospective cohort study to age 6 years

OBJECTIVES We investigated the relationship between breastfeeding, asthma and atopy, and child body mass index (BMI). METHODS From a prospective birth cohort (n = 2860) in Perth, Western Australia, 2195 children were followed up to age 6 years. Asthma was defined as doctor-diagnosed asthma and wheeze in the last year, and atopy was determined by skin prick test of 1596 children. Breastfeeding, BMI, asthma, and atopy were regressed allowing for confounders and the propensity score for overweight. RESULTS Using fractional polynomials, we found no association between breastfeeding and overweight. Less exclusive breastfeeding was associated with increased asthma and atopy, and BMI increased with asthma. CONCLUSIONS Less exclusive breastfeeding leads to increases in child asthma and atopy and a higher BMI is a risk factor for asthma.

Ratio of Omega-6 to Omega-3 Fatty Acids and Childhood Asthma

Asthma is a leading cause of morbidity for children and is a major public health problem in Australia. Ecological and temporal data suggest that dietary factors may have a role in recent increases in the prevalence of asthma. Aim: The aim of conducting this study was to investigate whether childhood asthma was associated with the ratio of omega 6 (n‐6) to omega 3 (n‐3) fatty acids in the diet (n‐6:n‐3). Method: The Western Australian Pregnancy Cohort Study is a prospective birth cohort of 2602 children. Using a nested case‐control cross‐sectional study design within this cohort, a group of children were identified as cases with current asthma at 6 or at 8 years of age or as controls with no asthma at 6 or at 8 years. Dietary details including n‐6 and n‐3 fatty acid intake data were collected by parent response to a questionnaire when the children were 8 years old. Logistical regression was used to compare quartiles of n‐6:n‐3 intake in cases and controls. Adjustment was made for covariates: gender, gestational age, breastfeeding, older siblings, maternal smoking during pregnancy, maternal age, maternal asthma, childs current age in months, body mass index, total energy intake, and antioxidant intake (vitamins A, C, E, and zinc). Results: A response rate of 83% was achieved by providing complete data from 335 children [49% cases with current asthma (n = 166), 51% controls (n = 169)]. Following adjustment for covariates the association between the ratio of n‐6:n‐3 fatty acids and risk for current asthma was statistically significant (p = 0.022). Conclusion: We found evidence for a modulatory effect of the dietary n‐6:n‐3 fatty acid ratio on the presence of asthma in children. Our results provide evidence that promotion of a diet with increased n‐3 fatty acids and reduced n‐6 fatty acids to protect children against symptoms of asthma is warranted.