Gordon W. Cran

Carbonated Soft Drink Consumption and Bone Mineral Density in Adolescence: The Northern Ireland Young Hearts Project

In an observational study of 1335 boys and girls aged 12 and 15 years, higher intakes of carbonated soft drinks (CSDs) were significantly associated with lower bone mineral density at the heel, but only in girls. Owing to the upward trend in CSD intake in adolescence, this finding may be of concern.

Physical activity, sports participation and risk factors in adolescents

The purpose of this study was to analyze the relationships between physical activity (ACT), including sports participation (SP) and antecedent risk factors for coronary heart disease (CHD), in a representative sample of adolescents from Northern Ireland, a region of high coronary mortality. Biological and behavioral risk factors were measured in a random sample of 1015 school children aged 12 and 15 yr. ACT and SP were assessed by self-report questionnaire, and relationships with biological risk factors were analyzed with stepwise multiple linear regression after controlling for potential confounders. Results showed that in 15-yr-old males ACT was beneficially associated with systolic blood pressure (P < 0.05), lipid profile, and cardiorespiratory fitness (both P < 0.01). In 15-yr-old females, SP was associated beneficially with fatness and cardiorespiratory fitness. Odds ratios calculated from logistic regression revealed that for the older children, a relatively small drop (-20%) in ACT (boys) or SP (girls) was significantly related to the probability of exposure to multiple risk factors. Overall, relationships were stronger for males rather than females and for older rather than younger children. This study provides further evidence for beneficial associations between ACT, SP, and CHD risk status in adolescents.

Fitness, fatness, and coronary heart disease risk in adolescents: the Northern Ireland Young Hearts Project

PURPOSE The purpose of this study was to examine the independence and relative strengths of association between coronary heart disease (CHD) risk status and both body fatness and cardiorespiratory (C-R) fitness in 12- and 15-yr-old adolescents. METHODS The study cohort consisted of 1015 schoolchildren aged 12 and 15 yr (251 12-yr-old boys, 258 12-yr-old girls, 252 15-yr-old boys, and 254 15-yr-old girls), representing a 2% random sample of each population group. For each child, height, weight, sexual maturity (pubertal status), skin-fold thicknesses (4 sites), blood pressure (random zero sphygmomanometer), nonfasting serum total, and high density lipoprotein (HDL)-cholesterol and C-R fitness (20-m shuttle run; 20-MST) were determined under standardized conditions. Socioeconomic status and habitual physical activity were also determined from questionnaire information. Multiple regression analyses were carried out to examine relationships between five CHD risk factors, and fitness and fatness and to examine the relative strengths of fitness and fatness on CHD risk status, correcting for potential confounding variables. RESULTS Our main findings were: 1) Relationships between fatness and CHD risk factors are invariably stronger than between fitness and the same risk factors. For example, partially adjusted standardized regression coefficients for 12-yr-old boys revealed significant relationships between all five CHD risk factors and fatness, compared with three of five for fitness. The corresponding figures for 12-yr-old girls were three of five (fatness) and one of five (fitness). Broadly similar results were apparent for 15-yr-olds. 2) Although relationships between fitness and CHD risk factors do not survive further adjustment for fatness, the relationships between fatness and CHD risk are more robust and are unaffected by further adjustment for fitness. CONCLUSION Our results indicate that the observed relationships between C-R fitness and CHD risk status in adolescents are mediated by fatness, whereas the observed relationships with fatness are independent of fitness. Primary prevention of CHD during childhood should therefore concentrate upon preventing or reversing undue weight gain.

Coronary risk factors in schoolchildren.

Death rates from coronary heart disease (CHD) in Northern Ireland are among the highest in the world. However, no data have been available to test the hypothesis that the high prevalence of CHD is reflected by the risk status of the childhood population. A randomly selected 2% population sample of 1015 children aged 12 and 15 years was studied to obtain baseline information on blood pressure, lipid profile, cigarette smoking, family history, physical activity, cardiorespiratory fitness, and dietary fat intake. Using available criteria thresholds, 15-23% displayed increased blood pressure, 12-25% had unfavourable lipid profiles, and 18-34% were overfat. In 15 year old children, 16-21% admitted being regular smokers, 26-34% displayed poor cardiorespiratory fitness, and 24-29% reported little physical activity in the previous week. Dietary analysis revealed relatively low polyunsaturated to saturated fatty acid ratios and high mean fat intakes, accounting for approximately 40% total daily energy. Despite the exclusion of family history from the analysis, 16% of the older children exhibited three or more risk factors. These results justify major concern about the level of potential coronary risk in Northern Ireland schoolchildren. Broadly based primary prevention strategies aimed at children are essential if future adult CHD mortality is to be reduced.

Parental recall of birthweight: A good proxy for recorded birthweight?

Recent evidence suggests potential associations between birthweight and disease in later life. For resource or other reasons recorded birthweight may be unavailable to researchers who have access to uniquely relevant outcome data. The present study examined the validity of parental recall of birthweight. Parents of 1015 males and females aged 12 and 15 years participating in the Young Hearts Study (a cluster random sample of 1015 males and females aged 12 and 15 years from post-primary schools in Northern Ireland) completed a questionnaire which included a question about their childs birthweight. The answer provided was compared with recorded birthweight obtained from archived computerised child health records with a cut-off point for inaccurate reporting set at ±227 g (1/2 lb). The influence of social class and weight at birth on accuracy of recall was also determined. A total of 84.8% of parents accurately recalled their childs birthweight to within 227 g. Parents from non-manual occupation social classes recalled birthweight more accurately than those from manual occupation social classes (88.0 vs. 82.6% accurate: χ2 = 4.81, p = 0.03). Parents of low birthweight infants tended to recall their birthweight less accurately than parents of normal weight infants: 76.1% accurate compared to 86.1% accurate: χ2 = 3.54, p = 0.06. Parents of high birthweight infants recalled their birthweight less accurately than parents of normal weight infants: 78.5% accurate: χ2 = 3.94, p = 0.05. In conclusion, parentally recalled birthweight may be a suitable proxy for recorded birthweight for population based research into disease in childhood and adolescence.

Long term health implications of fitness and physical activity patterns.

Northern Ireland has the highest incidence of coronary heart disease (CHD) in the world. The physical fitness, activity patterns, health knowledge, attitudes, and dietary habits of a random, stratified sample of 3211 Northern Irish children, comprising 1540 boys and 1671 girls, age range 11-18 years were examined. At all ages boys were significantly more active than girls. The most important finding was an appreciable decline in physical activity levels after the age of 14 years reaching extremely low levels in older girls. While 75% of exercise taken was not related to school, physical education classes constituted the only exercise taken by one third of pupils. Girls had healthier nutritional habits and were more inclined to employ weight control measures than boys. There was a preponderance of children with a higher body mass index indicating a tendency to obesity in the child population. Over 20% of school leavers of both sexes regularly smoked cigarettes and 20% regularly drank alcohol. The postulated relationship between childhood inactivity, adult sedentary lifestyle, and increased risk of CHD raises serious cause for concern regarding the future cardiovascular health of many children.

Nutrient intakes and impact of fortified breakfast cereals in schoolchildren.

OBJECTIVE: To report micronutrient intakes in Northern Ireland schoolchildren, and to establish the contribution of fortified breakfast cereal to overall nutrient intakes and achievement of current dietary recommendations. DESIGN: Analysis of dietary intakes and physical characteristics of participants in a randomly selected 2% population sample of 1015 schoolchildren aged 12 and 15 years in Northern Ireland during the 1990/1 school year. MAIN OUTCOME MEASURES: Dietary intakes, physical characteristics, and their association with consumption of fortified breakfast cereal. RESULTS: Mean micronutrient intakes were generally adequate with the exception of low intakes of folate (boys and girls) and iron (girls). Fortified breakfast cereals, consumed by a high proportion (94% boys; 83% girls) of the sample, were associated with higher daily intakes of most micronutrients and fibre and with a macronutrient profile consistent with current nutritional recommendations. Appreciable proportions of subjects who did not consume fortified breakfast cereals had daily intakes that fell below the lower reference nutrient intake for riboflavin, niacin, folate, vitamin B-12, and iron (girls). CONCLUSIONS: The results demonstrate the potential of fortification in contributing to micronutrient intakes of schoolchildren, particularly where requirements are high, or for those on marginal diets of low nutritional quality.

ESTIMATES OF FOOD AND MACRONUTRIENT INTAKE IN A RANDOM SAMPLE OF NORTHERN IRELAND ADOLESCENTS

Estimates of food consumption and macronutrient intake were obtained from a randomly selected population sample (2%) of 1015 adolescents aged 12 and 15 years in Northern Ireland during the 1990/1991 school year. Dietary intake was assessed by diet history with photographic album to estimate portion size. Reported median energy intakes were 11.0 and 13.1 MJ/d for boys aged 12 and 15 years respectively and 9.2 and 9.1 MJ/d for girls of these ages. Protein, carbohydrate and total sugars intakes as a percentage of total energy varied little between the age and sex groups and were approximately 11, 49 and 20% respectively of daily total energy intakes. Median dietary fibre intakes were approximately 20 and 24 g/d for boys aged 12 and 15 years respectively and 18 and 19 g/d for girls of these ages. Major food sources of energy (as a percentage of total energy intakes) were bread and cereals (15-18%), cakes and biscuits (12-14%), chips and crisps (13-14%), dairy products (9-11%), meat and meat products (9-11%) and confectionery (9%). Fruit and vegetable intakes were low at about 2.5% and 1.5% respectively of total energy intakes. Median fat intakes were high at 39% of total daily energy intakes. Major food sources of fat as a percentage of total fat intakes were from the food groupings: chips and crisps (16-19%), meat and meat products (14-17%), fats and oils (14-16%), cakes and biscuits (13-16%) and dairy products (12-15%). Median intakes of saturated fatty acids were also high at approximately 15% of daily total energy intake while intakes of monounsaturated fatty acids averaged 12% of daily total energy intake. Median polyunsaturated fatty acid (PUFA) intakes were low, comprising 5.2 and 5.5% of daily total energy intake for boys aged 12 and 15 years respectively and were lower than the PUFA intakes (5.9 and 6.3% of daily total energy intake) for girls of these ages. About 1.3% for boys and 1.4% for girls of daily total energy intake was in the form of n-3 PUFA. Ca and Mg intakes were adequate for both sexes. Based on these results, some concern about the dietary habits and related health consequences in Northern Ireland adolescents appears justified.

Trends in blood pressure over 10 years in adolescents: analyses of cross sectional surveys in the Northern Ireland Young Hearts project

Abstract Objective To examine secular trends in blood pressure over a 10 year period between two representative cohorts of adolescents from Northern Ireland. Design Repeat cross sectional study. Setting Randomly selected post-primary schools from Northern Ireland. Participants 1015 adolescents studied between 1989 and 1990, and 2017 adolescents studied between 1999 and 2001. Participants were aged 12 or 15 years. Main outcome measures Systolic and diastolic blood pressure measured by one observer in each study. Results The four groups for sex and age showed decreases in both systolic blood pressure (mean decrease 7.7 mm Hg to 10.0 mm Hg) and diastolic blood pressure (8.8 mm Hg to 11.0 mm Hg). These decreases were not accounted for by adjustment for potential confounders including age, height, body mass index, smoking, physical activity, aerobic fitness, and stratification of school by education board area and type. The findings were not altered by additional adjustment for social class, pubertal status, birth weight, and infant feeding. No evidence was found of systematic variation between observers. Conclusions Substantial decreases in systolic and diastolic blood pressure over the past decade in adolescents from Northern Ireland are likely to have important benefits to public health and may help offset the increasing risk of cardiovascular disease due to increases in obesity.

Clustering of Biological Risk Factors for Cardiovascular Disease and the Longitudinal Relationship with Lifestyle of an Adolescent Population: The Northern Ireland Young Hearts Project

Objective To determine whether clustering of biological cardiovascular disease (CVD) risk factors exists and to investigate the longitudinal relationship between lifestyle parameters (dietary intake, physical activity and smoking behaviour) and clustering of biological CVD risk factors, which was defined as belonging to one or more sex-specific ‘high-risk’ quartiles for the ratio between levels of total serum cholesterol and high-density lipoprotein cholesterol, diastolic blood pressure, body fatness (sum of four skinfolds) and cardiopulmonary fitness (number of laps accomplished on a 20 m shuttle-run test). Methods The study was part of the Northern Ireland Young Hearts Project, a 3-year observational longitudinal study concerning adolescent boys (n = 229) and girls (n = 230) who were initially aged 12 years. The longitudinal relationships were analysed with generalized estimating equations. Results Significant clustering of biological CVD risk factors was observed both for boys and for girls, but the stability over time was rather low. Smoking was the only lifestyle parameter related to this clustering and was observed only among girls (rate ratio 1.5, P<0.01); furthermore, none of the lifestyle parameters was significantly related to this clustering. Conclusions Because biological CVD risk factors tend to cluster, it is important to investigate these risk factors together. However, for subjects in this age group, according to our analysis, lifestyle parameters were hardly related to this clustering.