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Biomedical subjects

R A Cockington

Publications and source records attributed to R A Cockington.

At least 19 recordsLinked to original sources
PubMed2003

Predicting obesity in early adulthood from childhood and parental obesity.

OBJECTIVE: To determine the degree of tracking of adiposity from childhood to early adulthood, and the risk of overweight in early adulthood associated with overweight in childhood and parental weight status in a cohort of children born in the mid-1970s. DESIGN: Longitudinal observational study. SUBJECTS: Approximately 155 healthy boys and girls born in Adelaide, South Australia, 1975-1976 and their parents. MEASUREMENTS: Height and weight of subjects at 2 y, annually from 4 to 8 y, biennially from 11 to 15 y and at 20 y, and of parents when subjects were aged 8 y. Body mass index (BMI) of subjects converted to standard deviation scores and prevalence of overweight and obesity determined using worldwide definitions. Parents classified as overweight if BMI> or =25 kg/m(2). Tracking estimated as Pearson's correlation coefficient. Risk ratio used to describe the association between weight status at each age and parental weight status and weight status at 20 y and weight status at each earlier age, both unadjusted and adjusted for parental weight status. RESULTS: The prevalence of overweight/obesity increased with age and was higher than that reported in international reference populations. Tracking of BMI was established from 6 y onwards to 20 y at r-values >0.6, suggesting that BMI from 6 y is a good indicator of later BMI. Tracking was stronger for shorter intervals and for those subjects with both parents overweight compared with those with only one or neither parent overweight. Weight status at an earlier age was a more important predictor of weight status at 20 y than parental weight status, and risk of overweight at 20 y increased further with increasing weight status of parents. CONCLUSION: Strategies for prevention of overweight and targeted interventions for prevention of the progression of overweight to obesity are urgently required in school-aged children in order to stem the epidemic of overweight in the adult population.

Adolescent↗
PubMed2001

The impact of fetal size and length of gestation on 6-sulphatoxymelatonin excretion in adult life.

Recent studies have shown that intrauterine growth retardation or fetal distress in human infants is associated with a pronounced reduction in melatonin secretion during the first 3 months of life. It is not known whether these associations persist beyond infancy. We have therefore examined the relationship between birthsize and melatonin secretion in 159 men and women aged 20, born in Adelaide, South Australia. Melatonin secretion was estimated by analysing the overnight urinary excretion of 6-sulphatoxymelatonin. The overnight excretion ranged from 1.7 to 128.9 nmoles/subject, was higher in women than in men (46.5 vs 34.1 nmoles, P = 0.003) and was significantly negatively correlated with the body mass index (P = 0.006). Excretion correlated with both birthweight and ponderal index at birth (P = 0.04 and P = 0.01 respectively after adjustment for gestational age) and also fell with increased duration of gestation (P = 0.007). The effects of adult body mass index added to that of low birthweight in predicting 6-sulphatoxymelatonin excretion. These data suggest that urinary 6-sulphatoxymelatonin excretion was impaired in adults who were growth restricted prenatally or were delivered after 40 weeks gestation.

Adult↗
PubMed2001

Does fat intake predict adiposity in healthy children and adolescents aged 2--15 y? A longitudinal analysis.

OBJECTIVE: To investigate the relationship between food energy and macronutrient intake and body fatness assessed up to seven times between 2 and 15 y of age. DESIGN: Prospective, observational study. Generalised linear estimating equations were used to evaluate the longitudinal relationship between body fatness and macronutrient intake. Regression analysis was used to assess whether body fatness at a particular age was predicted by intake at any of the previous ages. SETTING: Community-based project in Adelaide, South Australia. SUBJECTS: In all 143--243 subjects from a representative birth cohort of healthy children recruited in 1975 and followed over 15 y. MAIN OUTCOME MEASURES: The dependent variables were body mass index (BMI), triceps (TC) and subscapular (SS) skinfolds, expressed as standard deviation (s.d.) scores at each age. The predictor variables were energy-adjusted macronutrient intake and total energy intake, estimated from a 3--4 day diet diary, the previous corresponding measure of body fatness, sex and parental BMI, TC or SS. RESULTS: Across 2--15 y energy-adjusted fat and carbohydrate intakes were respectively directly and inversely related to SS skinfold measures but not to either BMI or TC skinfold. The best predictor of fatness was previous adiposity, with the effect strengthening as the age interval shortened. Parental BMI, maternal SS and paternal TC contributed to the variance of the corresponding measure in children at some but not all ages. CONCLUSIONS: The current level of body fatness of the child and parental adiposity are more important predictors than dietary intake variables of risk of children becoming or remaining overweight as they grow.

Adolescent↗
PubMed2000

Alcohol consumption and insulin resistance in young adults.

BACKGROUND: Alcohol may have a cardioprotective effect. One possible mechanism is by reducing insulin resistance, a known cardiovascular risk factor. The aim of this study was to assess the relationship between alcohol consumption, insulin resistance and other parameters determining glucose tolerance in 154 young men and women. SUBJECTS AND METHODS: Subjects completed a questionnaire documenting weekly alcohol consumption. Insulin sensitivity and glucose tolerance were measured using the intravenous glucose tolerance test with minimal model analysis. Height, weight, usual level of exercise, smoking habits and socio-economic status were also recorded. RESULTS: Insulin sensitivity correlated inversely with body mass index (r = - 0.529, P < 0.001) but not with level of physical fitness. Women were significantly less insulin sensitive than men (4.19 and 5.63 104 min-1 pmol-1 L-1, respectively; P < 0.001). Insulin sensitivity correlated positively with alcohol consumption and this trend remained significant allowing for body mass index and gender (beta = 0.17, P < 0.014). First-phase insulin secretion showed a weak but non-significant trend in the opposite direction. Fasting glucose, fasting insulin and glucose tolerance showed no relationships with alcohol consumption. CONCLUSION: These data suggest a close relationship between alcohol consumption and insulin resistance in young adults. Regular alcohol consumption is associated with decreased insulin resistance and this may partly explain the cardioprotective effect of alcohol.

Adult↗
PubMed2000

Fetal growth and the physiological control of glucose tolerance in adults: a minimal model analysis.

Although there is now substantial evidence linking low birthweight with impaired glucose tolerance and type 2 diabetes in adult life, the extent to which reduced fetal growth is associated with impaired insulin sensitivity, defective insulin secretion, or a combination of both factors is not clear. We have therefore examined the relationships between birth size and both insulin sensitivity and insulin secretion as assessed by an intravenous glucose tolerance test with minimal model analysis in 163 men and women, aged 20 yr, born at term in Adelaide, South Australia. Birth size did not correlate with body mass index or fat distribution in men or women. Men who were lighter or shorter as babies were less insulin sensitive (P = 0.03 and P = 0.01, respectively), independently of their body mass index or body fat distribution. They also had higher insulin secretion (P = 0.007 and P = 0.006) and increased glucose effectiveness (P = 0.003 and P = 0.003). Overall glucose tolerance, however, did not correlate with birth size, suggesting that the reduced insulin sensitivity was being compensated for by an increase in insulin secretion and insulin-independent glucose disposal. There were no relationships between birth size and insulin sensitivity or insulin secretion in women. These results show that small size at birth is associated with increased insulin resistance and hyperinsulinemia in young adult life but that these relationships are restricted to the male gender in this age group.

Adult↗
PubMed1999

Reduced foetal growth and growth hormone secretion in adult life.

OBJECTIVES: Recent studies suggest that growth restriction or other adverse influences acting in utero or during early infancy lead to permanent alterations in growth hormone (GH) secretion. As GH secretion is known to predict cardiovascular risk, alterations in GH may contribute to the association between reduced foetal growth and cardiovascular disease. We have therefore assessed the relationship between birth size and GH secretion in a prospective study of young adults whose birth size was recorded and who have had their current blood pressure and glucose tolerance measured. DESIGN: Prospective cohort study PATIENTS: 153 healthy men and women, aged 20-21 years. MEASUREMENTS: Subjects carried out a timed overnight urinary collection for analysis of GH excretion. Insulin sensitivity and insulin secretion were measured using the intravenous glucose tolerance test with minimal model analysis. Blood pressure, height, weight, usual level of exercise, smoking habits, alcohol consumption, and socio-economic status were also recorded. RESULTS: GH excretion ranged from 0.01 to 41.8 microU per subject. It did not differ according to gender but was markedly reduced in obese subjects (P < 0.0001) Low birthweight was strongly associated with low GH excretion at age 20 years (P = 0.002). Low placental weight and short body length also predicted low GH (P = 0.02 and P = 0.04, respectively). These relationships were independent of other confounding factors including obesity. GH excretion was not independently related to current levels of blood pressure, insulin sensitivity or insulin secretion. CONCLUSIONS: Body size at birth predicts GH excretion in adult life. Low GH excretion in people who were small at birth may be one mechanism explaining their increased risk of cardiovascular disease.

Adult↗
PubMed1999

Bone growth from 11 to 17 years: relationship to growth, gender and changes with pubertal status including timing of menarche.

The tempo and change in bone growth during puberty in relation to physical growth is described in a cohort of 56 boys and 52 girls. Distal forearm bone width, mineral content and volumetric density, anthropometry and pubertal status were measured at ages 11, 13, 15 and 17 y, and bone age at 17 y. Bone width and mineral content increased independently with age for each pubertal stage. Volumetric density fell during early puberty and then increased rapidly. Maximal increase of all bone variables occurred earlier in girls than in boys and earliest for bone width, then mineral content, then density. In girls most change occurred in the 12 mo before and after menarche. The degree of tracking was similar to that for height. Bone growth followed physical growth but at a slower tempo. By age 17 y boys had attained 86% of the reference adult bone mineral content and volumetric density; girls had attained 93% of the reference adult bone mineral content and 94% of volumetric density. Those skeletally mature at 17 y had greater mineral content and volumetric density. To maximize peak bone mass, modifiable environmental factors should be optimized before the onset of puberty and be maintained throughout this period of rapid growth and beyond attainment of sexual maturity.

Adolescent↗
PubMed1999

The relationship between birth weight and blood pressure amplifies from childhood to adulthood.

OBJECTIVE: To investigate relationships between birth characteristics and blood pressure at age 20 years and to assess whether effects of birth weight on blood pressure are amplified from childhood to adulthood. DESIGN: A longitudinal study of 584 men and women from Adelaide, Australia, examined previously at 8 years and followed up at age 20 years. RESULTS: Birth weight was negatively associated with systolic pressure at age 20 years in men (regression coefficient 2.6 mmHg per kg; 95% confidence interval 0.7, 4.4) and women (regression coefficient 4.6 mmHg per kg; 95% confidence interval 2.9, 6.4), after adjustment for current weight There was an interaction with current size (P = 0.05 for men and P = 0.09 for women), such that effects were enhanced among individuals with relatively high weight or weight for height. Shortness at birth, thinness at birth, and low birth weight relative to placental weight were also associated with elevated systolic pressure at age 20 years. Effects of birth weight on blood pressure were stronger at age 20 than at age 8 years (P < 0.01 for men and P = 0.03 for women). This was not due simply to increased variability of blood pressure in adulthood. There were greater rises in blood pressure with age among individuals of relatively low birth weight. CONCLUSIONS: These findings are further evidence that poor fetal growth is associated with elevated blood pressure in later life. The results support the hypothesis that the relationship is amplified with increasing age.

Adolescent↗
PubMed1999

The autonomic control of heart rate and insulin resistance in young adults.

The pathophysiology of insulin resistance is unclear. A link between increased heart rate (HR) and insulin resistance suggests an association with sympathetic nervous system activity. To further evaluate this, we examined autonomic activity using spectral analysis of HR variability (HRV), which provides a measure of cardiac sympathovagal modulation, and related this to insulin sensitivity (Si) in 137 men and women (20 yr old). The HRV spectrum displays 2 major peaks: a high-frequency peak, reflecting vagal activity, and a low-frequency peak caused by vagal and sympathetic activity. The high-to-low ratio (HLratio) reflects sympathovagal balance. Si was measured, using the i.v. glucose tolerance test with minimal modeling, and HR data was derived from a 15-min supine electrocardiogram. Women were more insulin resistant than men (Si, 3.94 vs. 5.09 10(4) min(-1)/per pmol x L; P = 0.002), had higher HR (59 vs. 56 beats/min, P = 0.019), but had a higher HLratio (2.04 vs. 1.31, P = 0.001). In men (but not women), Si correlated with HR (r = -0.410, P = 0.001) and measures of HRV: HLratio (r = 0.291, P = 0.002) independently of body mass index. In conclusion, Si correlates with cardiac sympathovagal balance in men, but not women, suggesting gender differences in the autonomic modulation of insulin resistance.

Adult↗
PubMed1996

Placental weight, birth measurements, and blood pressure at age 8 years.

OBJECTIVE: To examine relationships between blood pressure during childhood and both placental weight and body size at birth, in an Australian population. DESIGN: A follow up study of a birth cohort, undertaken when cohort members were aged 8 years. SETTING: Adelaide, South Australia. SUBJECTS: 830 children born in the Queen Victoria Hospital in Adelaide, South Australia, during 1975-6. MAIN OUTCOME MEASURES: Systolic and diastolic blood pressure measured when the children were aged 8 years. RESULTS: Blood pressure at 8 years was positively related to placental weight and inversely related to birth weight, after adjusting for the child's current weight. For diastolic pressure there was a decrease of 1.0 mm Hg for each 1 kg increase in birth weight (95% confidence interval (CI) = -0.4 to 2.4) and an increase of 0.7 mm Hg for each 100 g increase in placental weight (95% CI = 0.1 to 1.3). Diastolic pressure was also inversely related to chest circumference at birth, independently of placental weight, with a decrease of 0.3 mm Hg for each 1 cm increase in chest circumference (95% CI = 0.2 to 0.5). CONCLUSIONS: These findings are further evidence that birth characteristics, indicative of fetal growth patterns, are related to blood pressure in later life.

Anthropometry↗
PubMed1995

A profile of heart disease risk factors and their relation to parents' education, fathers' occupation and family history of heart disease in 843 South Australian families: the Adelaide Children's WHO Collaborative Study.

OBJECTIVE: A study was conducted to determine whether the prevalence of risk factors among pre-adolescent children is associated with their parents' risk factor status and what influence family history of ischaemic heart disease (IHD) and socio-economic status (SES) had. METHODOLOGY: This was a cross-sectional study of 856 children, mean age 8.6 years, and their parents who underwent the World Health Organization and National Heart Foundation protocols for the study of arteriosclerosis precursors. Historical, demographic, anthropometric, clinical and biochemical outcome measures were used. RESULTS: There was the expected burden of illness reported for the grandparents and parents, with the latter conforming to their expected age group's heart disease risk factor status. The mean serum total cholesterol (TC) level for boys was 4.43 (+/- 0.79) mmol/L and girls 4.62 (+/- 0.84) mmol/L, with the 95th percentile for boys and girls combined being 5.88 mmol/L. The level corresponding to two standard deviations above the mean was 6.0 mmol/L. Childrens' IHD risk factor status reflected their parents' with TC, skin fold thickness and body mass index most closely correlated, followed by blood pressure. The greatest correlation was between the childrens' TC and their mothers'. Socio-economic status as assessed by the parents' education level and fathers' occupational status produced differences in their childrens' risk factors, with mother's level of education having the major influence. There was no impact of family history of IHD. CONCLUSIONS: From these results it would appear that screening of the pre-adolescent may be appropriate but longitudinal study will be important to establish this by documenting persistence of risk factor status. Also, it would appear that a child's future risk from IHD morbidity may be due to environmental influences mediated through differences in SES. As the level of IHD risk factors is reduced within the community, the extent of parent-child transmission of measurable IHD risk factors in families of high IHD risk may be reduced.

Child↗
PubMed1995

Health promotion using television in hospital waiting rooms: the Adelaide Children's Parent Education Project.

OBJECTIVES: The Adelaide Children's Hospital Parent Education Project was designed to determine the effect of the screening of health promotion programmes via closed circuit television facilities in hospital waiting rooms on parents' knowledge of child health issues. METHODOLOGY: A knowledge test was constructed with an internal consistency co-efficient of 0.95 and used to identify target groups of parents with low knowledge. The education programmes screened were aimed at the knowledge deficits. To assess the effects of the programmes an experiment was conducted using a post-test only/control group design, including a time delay. Days of the week were assigned randomly to programme days when health education programmes were screened and non-programme days when normal television programmes were screened. The experimental group was selected randomly from the attendance registers on programme days and the control group from non-programme days. RESULTS: The experimental group of parents gained substantial increases in knowledge with some knowledge scores increasing by nearly 70%. Overall there was a statistically significant difference between the knowledge scores of experimental and control groups. The recall of programme content by parents was notable in view of the fact that because of waiting times most only viewed part of the education programmes. Health-promoting behaviour changes were also reported. CONCLUSIONS: The screening of health programmes via hospital waiting room television significantly increases the health knowledge of viewers, although there is a decline over time.

Adult↗
PubMed1995

Serum lipids and apolipoproteins from 1 to 15 years: changes with age and puberty, and relationships with diet, parental cholesterol and family history of ischaemic heart disease.

We describe the pattern of change for serum lipids and apolipoproteins from 1 to 15 years of age in a cohort of 128 children, supplemented with 215 children from 11 years of age and 243 at 13 years of age. Total cholesterol (TC) decreased after infancy, increased in early puberty and then decreased to 15 years of age. Reciprocal changes in high (HDLC) and low (LDLC) density lipoprotein cholesterol occurred during each interval, with HDLC increasing from 13 to 15 years in both sexes. The correlation for TC between children of both sexes and mothers and fathers varied from 0.1 to 0.28 at 2-13 years. At 15 years of age the correlation between mothers: daughters increased to 0.31, decreased to 0.19 for fathers: daughters, but no association was present between either parent and their sons. There were no differences in mean lipid values for the sample grouped according to the extent of family history of early ischaemic heart disease (before 60 years of age). There were few significant associations between serum lipids, energy and nutrients. At 15 years of age inverse associations were present between TC and energy, protein, sugar, starch and fibre intakes, and a positive association with total fat intake.

Adolescent↗