Pauline M Emmett

Early life risk factors for obesity in childhood: cohort study

Abstract Objective To identify risk factors in early life (up to 3 years of age) for obesity in children in the United Kingdom. Design Prospective cohort study. Setting Avon longitudinal study of parents and children, United Kingdom. Participants 8234 children in cohort aged 7 years and a subsample of 909 children (children in focus) with data on additional early growth related risk factors for obesity. Main outcome measures Obesity at age 7 years, defined as a body mass index 3 95th centile relative to reference data for the UK population in 1990. Results Eight of 25 putative risk factors were associated with a risk of obesity in the final models: parental obesity (both parents: adjusted odds ratio, 10.44, 95% confidence interval 5.11 to 21.32), very early (by 43 months) body mass index or adiposity rebound (15.00, 5.32 to 42.30), more than eight hours spent watching television per week at age 3 years (1.55, 1.13 to 2.12), catch-up growth (2.60, 1.09 to 6.16), standard deviation score for weight at age 8 months (3.13, 1.43 to 6.85) and 18 months (2.65, 1.25 to 5.59); weight gain in first year (1.06, 1.02 to 1.10 per 100 g increase); birth weight, per 100 g (1.05, 1.03 to 1.07); and short (< 10.5 hours) sleep duration at age 3 years (1.45, 1.10 to 1.89). Conclusion Eight factors in early life are associated with an increased risk of obesity in childhood.

Association between postnatal catch-up growth and obesity in childhood: prospective cohort study

Abstract Objective: To identify predictors of postnatal catch-up growth from birth to two years and its relation to size and obesity at five years. Design: Regional prospective cohort study. Setting: Avon longitudinal study of pregnancy and childhood, United Kingdom. Subjects: 848 full term singletons from a 10% random sample of the Avon longitudinal study of pregnancy and childhood. Main outcome measures: Maternal birth weight, prepregnancy weight, pregnancy weight gain, height, smoking, and parity, and paternal height. Weight and length of infants at birth, two years, and five years expressed as standard deviation (SD) scores from the UK reference scores for 1990. Percentage fat mass and total fat mass (estimated from skinfolds) and waist circumference at five years. Results: Size at birth was representative of the national reference. Overall, 30.7% (260 of 848) of infants showed a gain in SD score for weight greater than 0.67 SD scores between zero and two years, indicating clinically significant catch-up growth. These children had lower weight, length, and ponderal index at birth than other children, and were more often from primiparous pregnancies. They also had taller fathers than other children, and their mothers had lower birth weights and were more likely to smoke during pregnancy. Children who showed catch-up growth between zero and two years were heavier, taller, and fatter (body mass index, percentage body fat, and waist circumference) at five years than other children. Conclusions: In this contemporary well nourished cohort, catch-up growth was predicted by factors relating to intrauterine restraint of fetal growth. Children who showed catch-up growth between zero and two years were fatter and had more central fat distribution at five years than other children. Mechanisms that signal and regulate early catch-up growth in the postnatal period may influence associations between small size at birth and risks for disease in adulthood.

Size at birth and early childhood growth in relation to maternal smoking, parity and infant breast-feeding: longitudinal birth cohort study and analysis

There is remarkably wide variation in rates of infancy growth, however, its regulation is not well understood. We examined the relationship between maternal smoking, parity, and breast- or bottle-feeding to size at birth and childhood growth between 0 and 5 y in a large representative birth cohort. A total of 1335 normal infants had weight, length/height, and head circumference measured at birth and on up to 10 occasions to 5 y old. Multilevel modeling (MLwiN) was used to analyze longitudinal growth data. Infants of maternal smokers were symmetrically small at birth (p < 0.0005) compared with infants of nonsmokers, however, showed complete catch-up growth over the first 12 mo. In contrast, infants of primiparous pregnancies were thin at birth (p < 0.0005), showed dramatic catch-up growth, and were heavier and taller than infants of nonprimiparous pregnancies from 12 mo onwards. Breast-fed infants were similar in size at birth than bottle-fed infants, but grew more slowly during infancy. Among infants who showed catch-up growth, males caught up more rapidly than females (p = 0.002). In conclusion, early postnatal growth rates are strongly influenced by a drive to compensate for antenatal restraint or enhancement of fetal growth by maternal-uterine factors. The mechanisms that signal catch-up or catch-down growth are unknown but may involve programming of appetite. The importance of nutrition on early childhood growth is emphasized by the marked difference in growth rates between breast- and bottle-fed infants. The sequence of fetal growth restraint and postnatal catch-up growth may predispose to obesity risk in this contemporary population.

Fruit, vegetables, and antioxidants in childhood and risk of adult cancer: the Boyd Orr cohort

Study objective: To examine associations between food and nutrient intake, measured in childhood, and adult cancer in a cohort with over 60 years follow up. Design and setting: The study is based on the Boyd Orr cohort. Intake of fruit and vegetables, energy, vitamins C and E, carotene, and retinol was assessed from seven day household food inventories carried out during a study of family diet and health in 16 rural and urban areas of England and Scotland in 1937–39. Participants: 4999 men and women, from largely working class backgrounds, who had been children in the households participating in the pre-war survey. Analyses are based on 3878 traced subjects with full data on diet and social circumstances. Main results: Over the follow up period there were 483 incident malignant neoplasms. Increased childhood fruit intake was associated with reduced risk of incident cancer. In fully adjusted logistic regression models, odds ratios (95% confidence intervals) with increasing quartiles of fruit consumption were 1.0 (reference), 0.66 (0.48 to 0.90), 0.70 (0.51 to 0.97), 0.62 (0.43 to 0.90); p value for linear trend=0.02. The association was weaker for cancer mortality. There was no clear pattern of association between the other dietary factors and total cancer risk. Conclusions: Childhood fruit consumption may have a long term protective effect on cancer risk in adults. Further prospective studies, with individual measures of diet are required to further elucidate these relations.

Identification of the obese child: adequacy of the body mass index for clinical practice and epidemiology.

OBJECTIVE: To assess the ability of simple definitions of BMI to successfully screen for children with high body fatness.DESIGN: We determined the sensitivity and specificity of the body mass index (BMI) by testing its ability to correctly identify children with high body fat percentage. Receiver operator characteristic (ROC) analyses were carried out using the top 5% of body fat percentage to define children as obese (true positives).SUBJECTS: Representative sample of 4175 7 y-old (88–92 month-old) children (2120 boys; 2055 girls) participating in the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC).RESULTS: The current obesity definition based on BMI (95th centile) had moderately high sensitivity (88%) and high specificity (94%). Sensitivity and specificity did not differ significantly between boys and girls. The ROC analysis showed that lower cut-offs applied to the BMI improved sensitivity with no marked loss of specificity: the optimum combination of sensitivity (92%) and specificity (92%) was at a BMI cut-off equivalent to the 92nd centile. Sensitivity of BMI using the new International Obesity Task Force (IOTF) cut-off for obesity was much lower, and differed significantly (P<0.001) between boys (46%) and girls (72%).CONCLUSIONS: Screening for childhood obesity using the BMI is specific, and can have moderately high sensitivity if an appropriate cut-off is chosen. New recommendations based on the IOTF approach to defining childhood obesity are associated with lower sensitivity, and sensitivity differs between boys and girls.

Infancy weight gain predicts childhood body fat and age at menarche in girls.

CONTEXT Rapid postnatal weight gain has been associated with subsequent increased childhood adiposity. However, the contribution of rapid weight gain during specific infancy periods is not clear. OBJECTIVE We aimed to determine which periods of infancy weight gain are related to childhood adiposity and also to age at menarche in UK girls. DESIGN, SETTING, AND PARTICIPANTS A total of 2715 girls from a prospective UK birth cohort study participated in the study. MAIN OUTCOME MEASURES Routinely measured weights and lengths at ages 2, 9, and 19 months were extracted from the local child health computer database. Body composition was assessed by dual-energy x-ray absorptiometry at age 10 yr, and age at menarche was assessed by questionnaire (categorized into three groups: <12.0, 12.0-13.0, and >13.0 yr). RESULTS Faster early infancy weight gain between 0 and 2 months and also 2 to 9 months were associated with increased body fat mass relative to lean mass at age 10 yr and also with earlier age at menarche. Each +1 unit gain in weight sd score between 0 and 9 months was associated with an odds ratio (95% confidence interval) = 1.48 (1.27-1.60) for overweight (body mass index > 85th centile) at 10 yr, and 1.34 (1.21-1.49) for menarche at less than 12 yr. In contrast, subsequent weight gain between 9 and 19 months was not associated with later adiposity or age at menarche. CONCLUSIONS In developed settings, rapid weight gain during the first 9 months of life is a risk factor for both increased childhood adiposity and early menarche in girls.

Dietary energy intake at the age of 4 months predicts postnatal weight gain and childhood body mass index

OBJECTIVE. Rapid infant weight gain has been shown to predict later obesity risk; however, it is unclear which factors influence infant diet and weight gain. The objective of this study was to determine whether different feeding patterns and energy intakes that are provided to infants affect body weight and BMI later in childhood. METHODS. This representative birth cohort study was conducted in the United Kingdom. Energy intake at age 4 months was estimated from 1-day unweighed dietary records in 881 infants and related to their childhood weight gain and BMI. RESULTS. Among formula- or mixed-fed infants (N = 582), energy intake was higher in first-born infants (mean ± SE: 2730 ± 29.4 kJ/day; n = 263) than in subsequent-born infants (2620.8 ± 25.2 kJ/day; n = 296). Energy intake at 4 months was also higher in infants who were given solid foods earlier (1–2 months: 2805.6 ± 50.4 kJ/day, n = 89; 2–3 months: 2658.6 ± 25.2 kJ/day, n = 339; 4+ months: 2587.2 ± 46.2 kJ/day, n = 111). Higher energy intake at 4 months predicted greater weight gain between birth to age 1, 2, or 3 years and larger body weight and BMI at ages 1 to 5 years. No significant associations were seen in breastfed infants (N = 299). CONCLUSIONS. Among formula- or mixed-fed infants, dietary energy intake at age 4 months predicted postnatal weight gain and childhood obesity risk. Both prenatal and postnatal factors may influence infant energy intake and postnatal weight gain.

Diet in childhood and adult cardiovascular and all cause mortality: the Boyd Orr cohort

Objective: To examine the association between childhood diet and cardiovascular mortality. Design: Historical cohort study. Setting: 16 centres in England and Scotland. Participants: 4028 people (from 1234 families) who took part in Boyd Orr’s survey of family diet and health in Britain between 1937 and 1939 followed up through the National Health Service central register. Exposures studied: Childhood intake of fruit, vegetables, fish, oily fish, total fat, saturated fat, carotene, vitamin C, and vitamin E estimated from household dietary intake. Main outcome measures: Deaths from all causes and deaths attributed to coronary heart disease and stroke. Results: Higher childhood intake of vegetables was associated with lower risk of stroke. After controlling for age, sex, energy intake, and a range of socioeconomic and other confounders the rate ratio between the highest and lowest quartiles of intake was 0.40 (95% confidence interval 0.19 to 0.83, p for trend 0.01). Higher intake of fish was associated with higher risk of stroke. The fully adjusted rate ratio between the highest and lowest quartile of fish intake was 2.01 (95% confidence interval 1.09 to 3.69, p for trend 0.01). Intake of any of the foods and constituents considered was not associated with coronary mortality. Conclusions: Aspects of childhood diet, but not antioxidant intake, may affect adult cardiovascular risk.

Dietary patterns in pregnancy and associations with socio-demographic and lifestyle factors.

Objective:To obtain distinct dietary patterns in the third trimester of pregnancy using principal components analysis (PCA); to determine associations with socio-demographic and lifestyle factors.Design and methods:A total of 12 053 pregnant women partaking in a population-based cohort study recorded current frequency of food consumption via questionnaire in 1991–1992. Dietary patterns identified using PCA were related to social and demographic characteristics and lifestyle factors.Results:Five dietary patterns were established and labelled to best describe the types of diet being consumed in pregnancy. The ‘health conscious’ component described a diet based on salad, fruit, rice, pasta, breakfast cereals, fish, eggs, pulses, fruit juices, white meat and non-white bread. The ‘traditional’ component loaded highly on all types of vegetables, red meat and poultry. The ‘processed’ component was associated with high-fat processed foods. The ‘confectionery’ component was characterized by snack foods with high sugar content and the final ‘vegetarian’ component loaded highly on meat substitutes, pulses, nuts and herbal tea and high negative loadings were seen with red meat and poultry. There were strong associations between various socio-demographic variables and all dietary components; in particular, a ‘health conscious’ diet was positively associated with increasing education and age and non-white women. There was a negative association with increased parity, single, non-working women, those who smoked and who were overweight pre-pregnancy. Opposite associations were seen with the ‘processed’ component.Conclusions:Distinct dietary patterns in pregnancy have been identified. There is clear evidence of social patterning associated with the dietary patterns, these social factors need to be accounted for in future studies using dietary patterns. This study will form the basis for further work investigating pregnancy outcome.

Feeding Symptoms, Dietary Patterns, and Growth in Young Children With Autism Spectrum Disorders

OBJECTIVE: To investigate the feeding, diet and growth of young children with autism spectrum disorders (ASD). METHOD: Data on feeding and food frequency were collected by questionnaires completed at 6, 15, 24, 38 and 54 months by participants in the Avon Longitudinal Study of Parents and Children. A food variety score was created, and the content of the diet was calculated at 38 m. The feeding and dietary patterns of 79 children with ASD were compared with 12 901 controls. RESULTS: The median ages of ASD children were 28 months at referral and 45 months at diagnosis. ASD infants showed late introduction of solids after 6 months (p = .004) and were described as “slow feeders” at 6 months (p = .04). From 15–54 months ASD children were consistently reported to be “difficult to feed” (p < .001) and “very choosy” (p < .001). From 15 months, the ASD group had a less varied diet than controls, were more likely to have different meals from their mother from 24 months, and by 54 months 8% of ASD children were taking a special diet for “allergy.” ASD children consumed less vegetables, salad and fresh fruit, but also less sweets and fizzy drinks. At 38 months intakes of energy, total fat, carbohydrate and protein were similar, but the ASD group consumed less vitamins C (p = .02) and D (p = .003). There were no differences in weight, height or BMI at 18 months and 7 years, or in hemoglobin concentrations at 7 years. CONCLUSIONS: ASD children showed feeding symptoms from infancy and had a less varied diet from 15 months, but energy intake and growth were not impaired.