Siobhan Hickling

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.

Long term survival after evidence based treatment of acute myocardial infarction and revascularisation: follow-up of population based Perth MONICA cohort, 1984-2005

Objective To examine trends in long term survival in patients alive 28 days after myocardial infarction and the impact of evidence based medical treatments and coronary revascularisation during or near the event. Design Population based cohort with 12 year follow-up. Setting Perth, Australia. Participants 4451 consecutive patients with a definite acute myocardial infarction according to the World Health Organization MONICA (monitoring trends and determinants in cardiovascular disease) criteria admitted to hospital during 1984-7, 1988-90, and 1991-3. Main outcome measures All cause mortality identified from official mortality records and the hospital morbidity data, with death from cardiovascular disease as a secondary end point. Results In the 1991-3 cohort, 28 day survivors of acute myocardial infarction had a 7.6% absolute event reduction (95% confidence interval 4% to 11%) or a 28% lower relative risk reduction (16% to 38%), unadjusted for risk of death, over 12 years after the incident admission compared with the 1984-7 cohort, similar to the survival of the 1988-90 cohort. The improved survival for the 1991-3 cohort persisted after adjustment for demographic factors, coronary risk factors, severity of disease, and event complications with an adjusted relative risk reduction of 26% (14% to 37%), but this was not apparent after further adjustment for medical treatments in hospital and coronary revascularisation procedures within 12 months of the incident myocardial infarction. Conclusion The improving trends in 12 year survival after a definite acute myocardial infarction are associated with progressive use of evidence based treatments during the initial admission to hospital and in the 12 months after the event. These changes in the management of acute myocardial infarction are probably contributing to the continuing decline in mortality from coronary heart disease in Australia.

Population Trends of Recurrent Coronary Heart Disease Event Rates Remain High

Background— Survivors of nonfatal coronary heart disease (CHD) can reduce their risk of further events by various preventive interventions. The impact of such measures as delivered over 11 years, on population rates of subsequent major CHD events, has not been extensively studied. This study determined population trends in the prevalence of clinically manifest CHD and the proportion of major CHD events that occur in this population. Methods and Results— A population longitudinal person-based event-linked file of CHD extracted from State Hospital Morbidity Data and Death Registry for 1980 to 2005 was used to identify, for each year from 1995 to 2005, survivors who had a hospitalization for CHD over the previous 15 years (population with established CHD), and to examine the occurrence of CHD death and hospitalization with a principal diagnosis of myocardial infarction in both populations with and without established CHD. The average annual age-standardized prevalence of CHD in the Perth metropolitan region (population 1.6 million) was 28 373 (8.8%) in men and 14 966 (4.0%) in women. Age-specific prevalence increased exponentially with age, from <1% in 35 to 39 age group to 42% in 80 to 84 age group in men and half that in women. The percentage of total CHD events (n=28 941) that occurred in the population with established CHD was approximately 43% in both men and women, 55% and 51%, respectively, for CHD death and 35% and 36% for nonfatal myocardial infarction. Conclusions— More than 40% of major CHD events annually occur in persons with manifest disease, highlighting the imperative to implement systems of care that support effective secondary prevention.

Impact of voluntary folate fortification on plasma homocysteine and serum folate in Australia from 1995 to 2001: a population based cohort study.

Study objective: To investigate the effect of the voluntary folate fortification policy in Australia on serum folate and total plasma homocysteine (tHcy) concentrations. Design: Population based cohort study. Setting: Perth, Western Australia. Participants: Men and women aged 27 to 77 years (n = 468), who were originally randomly selected from the Perth electoral roll. The cohort was surveyed in 1995/96 before widespread introduction of folate fortification of a variety of foods, and followed up on two occasions, firstly in 1998/99 and again in 2001, when a moderate number of folate fortified foods were available. Subjects with abnormal serum creatinine concentrations at baseline were excluded from this analysis. Main results: Repeated measures analysis of variance was used to determine changes in serum folate and tHcy over the three surveys and to assess whether time trends were related to age, sex, MTHFR C677T genotype, or consumption of folate fortified foods. An increase (38%) in mean serum folate (p<0.0005) and a decrease (21%) in mean tHcy (p<0.0005) were seen after introduction of the voluntary folate fortification policy in Australia. Serum folate was consistently higher (p = 0.032) and tHcy was consistently lower (p = 0.001) in subjects who consumed at least one folate fortified food compared with subjects who did not consume any folate fortified foods in the previous week. The time related changes in serum folate and tHcy were affected only by intake of folate fortified foods (p<0.0005) and not by any other measured variables including age, sex, or MTHFR genotype. Conclusion: Voluntary fortification of foods with folate in Australia has been followed by a substantial increase in serum folate and decrease in tHcy in the general population.

Temporal trends in the incidence and recurrence of hospitalised atherothrombotic disease in an Australian population, 2000–07: data linkage study

Objectives To examine temporal trends in the incidence and recurrence of hospitalised coronary heart disease (CHD), cerebrovascular disease (CeVD) and peripheral arterial disease (PAD) separately and combined, and by the history of all forms of atherothrombotic disease (ATD). Design Population-based longitudinal data linkage study. Setting Western Australia. Participants All patients aged 35–84 years hospitalised in Western Australia for CHD, CeVD or PAD from 2000 to 2007. Main Outcome Measures Age-standardised incidence and recurrence rates of CHD, CeVD and PAD stratified by ATD history, sex and age. Results 107 576 events (65.9% men) were identified; 70% of all admissions were for CHD. In patients without a history of any ATD, incidence rates declined significantly in all groups, although the reduction in incident CHD in women was marginal (−0.7%/year, 95% CI −1.5 to +0.1%). The largest annual reductions in incidence rates were for PAD (men, −6.4%/year, 95% CI −7.7 to −5.0%; women, −5.4%/year, 95% CI −7.2 to −3.6%) and CeVD in women (−4.0%/year, 95% CI −5.0 to −3.0%). Falls in overall recurrence rates were greatest for CeVD (men, −3.2%/year, 95% CI −4.7 to −1.6%; women −4.6%/year, 95% CI −6.4 to −2.7%). Trends across all categories of polyvascular ATD were generally downward, although not all changes were statistically significant. Conclusion The incidence and recurrence rates of hospitalised ATD have decreased over time, including in patients with disease involving multiple vascular territories. This implies that primary and secondary prevention strategies have been broadly effective. However, high absolute rates of recurrence and limited reduction in 35–54-year-old individuals highlight patient groups to target to reduce further the burden of ATD.

Are the associations between diet and C-reactive protein independent of obesity?

OBJECTIVES To determine the relative magnitude of the effect of dietary factors on circulating C-reactive protein (CRP) levels, controlling for BMI. METHODS 1808 men and 2269 women attended the 1994/95 follow-up survey from the Busselton Health Study, Australia. A composite diet score was derived from a short questionnaire. Height and weight were measured. RESULTS After controlling for BMI, CRP levels were associated with red meat intake (males only, p=0.001), fruit intake (males p<0.0001, females p=0.029), potato intake (males p=0.008, females p=0.029), using wholemeal bread (males p=0.014, females p=0.018), using polyunsaturated fats as a spread and in cooking (females only, p=0.005), and rarely or never adding salt to food (males p=0.012, females p=0.004). The overall diet score was significantly (negatively) related to CRP in males (p<0.0001) and females (p<0.0001). The relative decrease in CRP from a moderately healthy diet, compared to an unhealthy diet was 37% in men and 24% in women. This was comparable to a difference in BMI of at least 3 kg/m(2) (or a difference in weight of approximately 9 kg for a person of average height). CONCLUSION A healthy diet and lower weight have independent beneficial effects of similar magnitude on CRP levels.

Diet in the early years of life influences cognitive outcomes at 10 years: A prospective cohort study

The aim of this study was to investigate the association between diet during the first 3 years of life and cognitive outcomes at 10 years of age.

The Relationship between Nutrition in Infancy and Cognitive Performance during Adolescence

Objectives: In this study, we aimed to investigate the long-term associations between breastfeeding duration during infancy, diet quality as measured by a diet score at 1 year of age, and cognitive performance during adolescence. Methods: Participants (n = 717) were recruited from the West Australian Pregnancy Cohort (Raine) Study, a prospective longitudinal study of 2868 children and their families based in Perth, WA, Australia. Breastfeeding duration and an early diet score at age 1 year were used as the main predictor variables, while a computerized cognitive battery (CogState) was used to assess adolescents’ cognitive performance at 17 years. The diet score, which has seven food group components, was based on a 24-h recall questionnaire completed by the mother at 1 year of age. A higher diet score represents a better, more nutritious eating pattern. Associations between breastfeeding duration, diet score, and cognitive performance were assessed in multivariable regression models. Results: Higher diet scores at 1 year representing better diet quality were significantly associated with faster reaction times in cognitive performance at 17 years [Detection Task (DET): β = −0.004, 95% CI: −0.008; 0.000, p = 0.036; Identification Task (IDN): β = −0.004, 95% CI: −0.008; 0.000, p = 0.027]. Breastfeeding duration (≥4 months) was also significantly associated with a shorter reaction time, but only for males (DET: β = −0.026, 95% CI: −0.046; −0.006, p = 0.010). Conclusion: Nutrition in early childhood may have a long-term association with fundamental cognitive processing speed, which is likely to be related to enhanced brain development in the first year of life.

Low intake of B-vitamins is associated with poor adolescent mental health and behaviour

OBJECTIVE The current prevalence of mental health problems in Western populations is approximately 20% and half of all adult mental health disorders are estimated to originate in adolescence. Diet plays an important role in modulating psychological wellbeing and B-vitamins are vital for the synthesis of neurotransmitters such as serotonin. We aimed to examine the relationship between B-group vitamins and adolescent mental health and behaviour. METHODS This is a cross-sectional analysis of the West Australian Pregnancy Cohort (Raine) Study. The 17-year follow-up included collection of a food frequency questionnaire allowing B-vitamin intake calculation. Mental health was assessed using the Youth Self Report (YSR) which measures total, internalising (withdrawn/depressed) and externalising (aggressive/delinquent) behaviour scores. Multiple linear regression was used to analyse associations between B-vitamins and mental health with adjustment for relevant confounders (n=709). RESULTS Lower intake of vitamins B1, B2, B3, B5, B6, and folate was associated with higher externalising behaviour scores (p ≤ 0.05). Reduced intake of vitamin B6 and folate was associated with higher internalising behaviour scores (p ≤ 0.05). CONCLUSIONS Poor nutrition may contribute to the pathogenesis of mental health problems in adolescence. The role of B-vitamins requires further investigation in randomised controlled trials.

Dietary intake in population-based adolescents: support for a relationship between eating disorder symptoms, low fatty acid intake and depressive symptoms

BACKGROUND Relatively little is known about the dietary intake and nutritional status of community-based individuals with eating disorders. This research aimed to: (i) describe the dietary intake of population-based adolescents with an eating disorder and (ii) examine associations between eating disorder symptoms, fatty acid intake and depressive symptoms in adolescents with and without an eating disorder. METHODS Data were drawn from the Western Australian Pregnancy Cohort (Raine) Study, a population-based cohort study that has followed participants from birth to young adulthood. This research utilised self-report data from the 17-year Raine Study assessment. Participants comprised 429 female adolescents who completed comprehensive questionnaire measures on dietary intake, eating disorder symptoms and depressive symptoms. RESULTS Adolescents with an eating disorder (n = 66) reported a significantly lower intake of total fat, saturated fat, omega-6 fatty acid, starch, vitamin A and vitamin E compared to adolescents without an eating disorder (n = 363). Adolescents with an eating disorder and pronounced depressive symptoms (n = 23) also reported a significantly lower intake of polyunsaturated fat and omega-3 and omega-6 fatty acid than adolescents with an eating disorder but no marked depression (n = 43). In the eating disorder sample but not the control sample, omega-3 and omega-6 fatty acid correlated significantly and negatively with eating disorder symptoms and with depressive symptoms. CONCLUSIONS Support is provided for a relationship between low omega-3 and omega-6 fatty acid intake and depressive symptoms in adolescents with eating disorders. Research is needed to examine the feasibility and effectiveness of fatty acid supplementation in this high-risk group.