G L Ambrosini

The association between dietary patterns and mental health in early adolescence

OBJECTIVEnTo investigate the associations between dietary patterns and mental health in early adolescence.nnnMETHODnThe 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gender and maternal education at pregnancy.nnnRESULTSnHigher total (b=2.20, 95% CI=1.06, 3.35), internalizing (withdrawn/depressed) (b=1.25, 95% CI=0.15, 2.35) and externalizing (delinquent/aggressive) (b=2.60, 95% CI=1.51, 3.68) CBCL scores were significantly associated with the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).nnnCONCLUSIONnThese 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.

The Western Dietary Pattern Is Prospectively Associated With Nonalcoholic Fatty Liver Disease in Adolescence

OBJECTIVES:Poor dietary habits have been implicated in the development of nonalcoholic fatty liver disease (NAFLD); however, little is known about the role of specific dietary patterns in the development of NAFLD. We examined prospective associations between dietary patterns and NAFLD in a population-based cohort of adolescents.METHODS:Participants in the Western Australian Pregnancy Cohort (Raine) Study completed a food frequency questionnaire at 14 years and had liver ultrasound at 17 years (n=995). Healthy and Western dietary patterns were identified using factor analysis and all participants received a z-score for these patterns. Prospective associations between the dietary pattern scores and risk of NAFLD were analyzed using multiple logistic regression.RESULTS:NAFLD was present in 15.2% of adolescents. A higher Western dietary pattern score at 14 years was associated with a greater risk of NAFLD at 17 years (odds ratio (OR) 1.59; 95% confidence interval (CI) 1.17–2.14; P<0.005), although these associations were no longer significant after adjusting for body mass index at 14 years. However, a healthy dietary pattern at 14 years appeared protective against NAFLD at 17 years in centrally obese adolescents (OR 0.63; 95% CI 0.41–0.96; P=0.033), whereas a Western dietary pattern was associated with an increased risk of NAFLD.CONCLUSIONS:A Western dietary pattern at 14 years in a general population sample was associated with an increased risk of NAFLD at 17 years, particularly in obese adolescents. In centrally obese adolescents with NAFLD, a healthy dietary pattern may be protective, whereas a Western dietary pattern may increase the risk.

Prospective associations between sugar-sweetened beverage intakes and cardiometabolic risk factors in adolescents

Background: High sugar-sweetened beverage (SSB) consumption is associated with cardiometabolic disturbances in adults, but this relation is relatively unexplored in children and adolescents. Objective: We tested the hypothesis that higher SSB intakes are associated with increases in cardiometabolic risk factors between 14 and 17 y of age. Design: Data were provided by 1433 adolescent offspring from the Western Australian Pregnancy Cohort (Raine) Study. At 14 and 17 y of age, SSB intakes were estimated by using a food-frequency questionnaire; body mass index (BMI), waist circumference, blood pressure, fasting serum lipids, glucose, and insulin were measured, and overall cardiometabolic risk was estimated. Prospective associations between cardiovascular disease risk factors and SSB intake were examined with adjustment for age, pubertal stage, physical fitness, socioeconomic status, and major dietary patterns. Results: The average SSB intake in consumers (89%) was 335 g/d or 1.3 servings/d. Girls who moved into the top tertile of SSB consumption (>1.3 servings/d) between 14 and 17 y of age had increases in BMI (3.8%; 95% CI: 1.8%, 5.7%), increased overweight and obesity risk (OR: 4.8, 95% CI: 2.1, 11.4), and greater overall cardiometabolic risk (OR: 3.2; 95% CI: 1.6, 6.2) (all P-trend ≤ 0.001). Girls and boys who moved into the top tertile of SSB intake showed increases in triglycerides (7.0–8.4%; P-trend ≤ 0.03), and boys showed reductions in HDL cholesterol (−3.1%; 95% CI: −6.2%, 0.1%; P-trend < 0.04) independent of BMI. Some associations were attenuated after adjustment for major dietary patterns. Conclusion: Increased SSB intake may be an important predictor of cardiometabolic risk in young people, independent of weight status.

Identification of a dietary pattern prospectively associated with increased adiposity during childhood and adolescence

Background:Specific dietary risk factors for excess adiposity in young people are poorly understood. However, studies in adults suggest dietary energy density, fat and fibre are critical dietary factors.Objective:To examine longitudinal relationships between a dietary pattern (DP) characterised by dietary energy density, % total energy from fat and fibre density and fat mass (FM) in children from 7 to 15 years of age.Design:Subjects were 6772 children from the UK Avon Longitudinal Study of Parents and Children. Dietary intake was assessed using a 3-day food diary at 7, 10 and 13 years of age. An energy-dense, high-fat, low-fibre DP was identified using reduced rank regression and subjects scored for the DP at each age. FM was measured at 11, 13 and 15 years and FM index (FMI) calculated as FM/height(x). Longitudinal models were adjusted for dietary misreporting, physical activity and maternal factors.Results:DP z-scores at all ages were positively associated with later FMI. A 1 s.d. unit increase in DP z-score was longitudinally associated with an average increase in FMI z-score of 0.04 s.d. units (95% confidence interval (CI), 0.01–0.07). For each 1 s.d. unit increase in DP z-score, the odds of being in the highest quintile for FMI (as a marker of excess adiposity) increased by 13% (95% CI, 1–27%).Conclusions:Dietary habits during childhood are associated with increased adiposity in adolescence, with specific implications for dietary energy density, fat and fibre intake. Improving diet quality may reduce the risk of obesity in young people.

Vitamin A and cancer prevention II: Comparison of the effects of retinol and β-carotene

Former blue asbestos workers known to be at high risk of asbestos‐related diseases, particularly malignant mesothelioma and lung cancer, were enrolled in a chemo‐prevention program using vitamin A. Our aims were to compare rates of disease and death in subjects randomly assigned to β‐carotene or retinol. Subjects were assigned randomly to take 30 mg/day β‐carotene (512 subjects) or 25,000 IU/day retinol (512 subjects) and followed up through death and cancer registries from the start of the study in June 1990 till May 1995. Comparison between groups was by Cox regression in both intention‐to‐treat analyses and efficacy analyses based on treatment actually taken. Median follow‐up time was 232 weeks. Four cases of lung cancer and 3 cases of mesothelioma were observed in subjects randomised to retinol and 6 cases of lung cancer and 12 cases of mesothelioma in subjects randomised to β‐carotene. The relative rate of mesothelioma (the most common single cause of death in our study) for those on retinol compared with those on β‐carotene was 0.24 (95% CI 0.07–0.86). In the retinol group, there was also a significantly lower rate for death from all causes but a higher rate of ischaemic heart disease mortality. Similar results were found with efficacy analyses. Our results confirm other findings of a lack of any benefit from administration of large doses of synthetic β‐carotene. The finding of significantly lower rates of mesothelioma among subjects assigned to retinol requires further investigation. Int. J. Cancer 75:362–367, 1998.

The reliability of a food frequency questionnaire for use among adolescents

Background:Accurate measurement of dietary intake is essential for understanding the long-term effects of adolescent diet on chronic disease risk. However, adolescents may have limited food knowledge and ability to quantify portion sizes and recall dietary intake. Therefore, food frequency questionnaires (FFQs) deemed appropriate for use among adults may not be suitable for adolescents.Objectives:To evaluate an FFQ in comparison with a 3-day food record (FR) in 14-year olds participating in a population-based cohort study in Western Australia.Methods:Nutrient intakes estimated by a semi-quantitative FFQ were compared with those from a 3-day FR using Bland & Altman limits of agreement (LOA), tertile classifications and Pearsons correlation coefficients.Results:A total of 785 adolescents provided data from both dietary methods. Mean agreement between the FR and FFQ ranged from 73 (starch) to 161% (vitamin C). The LOA ranged from 27 (retinol) to 976% (carotene), with most nutrients being overestimated by the FFQ. For most nutrients, agreement between the two methods varied significantly with the magnitude of intake. Pearsons r ranged from 0.11 (polyunsaturated fats) to 0.52 (riboflavin). The FFQ classified 80 to 90% of subjects’ nutrient intakes into the same or adjacent tertile as their FR. Boys performed slightly better for all of these indices.Conclusions:Agreement between individual FFQ and FR nutrient intakes was less than ideal. However, the FFQ was able to correctly rank a reasonable proportion of adolescents.

Childhood dietary patterns and later obesity: a review of the evidence

A range of individual nutrients and foods have been suggested to increase obesity risk in childhood, but the evidence is inconsistent. Dietary patterns that summarise the whole diet may, however, be more informative. The aim of the present paper was to systematically review the current evidence pertaining to overall dietary patterns in childhood and later obesity risk. Studies eligible for review identified childhood dietary patterns using an empirical method, i.e. principal components analysis, factor analysis or reduced rank regression, and reported their prospective associations with an obesity-related outcome. Literature searches identified 166 studies and of these, seven met the eligibility criteria. Despite differences between studies, a common dietary pattern was identified in all seven studies that was high in energy-dense, high-fat and low-fibre foods. The quality of studies varied, however; the four studies reporting positive associations between this type of dietary pattern and later obesity risk were of consistently higher quality than those reporting null associations. The balance of evidence from this systematic review indicates that dietary patterns that are high in energy-dense, high-fat and low-fibre foods predispose young people to later overweight and obesity. It also highlights that examining multiple dietary factors within a dietary pattern may better explain obesity risk than individual nutrients or foods. However, more prospective studies are needed and dietary pattern research requires greater rigour and focus, to further clarify the role of dietary factors in the aetiology of obesity and inform future interventions.

Vitamin A and cancer prevention I: Observations in workers previously exposed to asbestos at Wittenoom, Western Australia

Our aim was to describe a vitamin A‐based cancer prevention program for former asbestos workers and to check for possible harmful effects by comparing rates of disease and death in study subjects with subjects who chose not to join. All subjects had been occupationally exposed to crocidolite at Wittenoom Gorge between 1943 and 1966; 1,677 subjects indicated interest in the program and 1,203 joined between June 1990 and May 1995. Comparison subjects consisted of 996 former workers known to be alive in Western Australia in 1990 who did not join the program. Program subjects were provided with annual supplies of vitamin A (either synthetic β‐carotene or retinol), help in quitting smoking and dietary advice. The comparison group received only mail contact. Both groups were followed up to December 1994 for vital status and cancer information, and rates of cancer and death from various causes were compared. Mortality in both groups was higher than expected (standardised mortality ratio 1.23 in program subjects and 1.67 in comparison subjects). After adjustment for age, smoking and asbestos exposure, the relative rates in participants compared with non‐participants was below 1 for all examined cancers and causes of death. For mesothelioma and lung cancer, group differences increased with time from entry, whereas other differences dissipated with time. No significant side effects were reported. In conclusion, program participants had significantly lower mortality than non‐participants, but the rates of the 2 groups converged with time. Int. J. Cancer 75:355–361, 1998.

Serum levels of folate, lycopene, β-carotene, retinol and vitamin E and prostate cancer risk

Previous studies relating increased serum levels of folate and fat-soluble vitamins to prostate cancer risk have variously shown null associations or to either decrease or increase the risk of developing prostate cancer. Prospective studies of serum folate levels have been reported to show a null association and increased serum levels to either decrease or increase the risk of subsequently developing prostate cancer. Similarly, serum β-carotene and lycopene levels have either been reported to be inversely correlated or not associated with prostate cancer risk. Using a prospective nested case-control study design, which minimized the possibility of disease effects on serum-vitamin concentrations, we report null associations for serum concentrations of folate, lycopene, β-carotene, vitamin A and vitamin E, and subsequent development of prostate cancer.

The risk of lung cancer with increasing time since ceasing exposure to asbestos and quitting smoking

Objectives: To examine if the risk of lung cancer declines with increasing time since ceasing exposure to asbestos and quitting smoking, and to determine the relative asbestos effect between non-smokers and current smokers. Methods: A cohort study of 2935 former workers of the crocidolite mine and mill at Wittenoom, who responded to a questionnaire on smoking first issued in 1979 and on whom quantitative estimates of asbestos exposure are known. Conditional logistic regression was used to relate asbestos exposure, smoking category, and risk of lung cancer. Results: Eighteen per cent of the cohort reported never smoking; 66% of cases and 50% of non-cases were current smokers. Past smokers who ceased smoking within six years of the survey (ORu200a=u200a22.1, 95% CI 5.6 to 87.0), those who ceased smoking 20 or more years before the survey (ORu200a=u200a1.9, 95% CI 0.50 to 7.2), and current smokers (<20 cigarettes per day (ORu200a=u200a6.8, 95% CI 2.0 to 22.7) or >20 cigarettes per day (ORu200a=u200a13.2, 95% CI 4.1 to 42.5)) had higher risks of lung cancer compared to never smokers after adjusting for asbestos exposure and age. The asbestos effect between non-smokers and current smokers was 1.23 (95% CI 0.35 to 4.32). Conclusion: Persons exposed to asbestos and tobacco but who subsequently quit, remain at an increased risk for lung cancer up to 20 years after smoking cessation, compared to never smokers. Although the relative risk of lung cancer appears higher in never and ex-smokers than in current smokers, those who both smoke and have been exposed to asbestos have the highest risk; this study emphasises the importance of smoking prevention and smoking cessation programmes within this high risk cohort.