No description available.

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No description available.

No description available.

No description available.

N/A / Thesis / Master of Science (MS)

Background: Pregnancy lifestyle interventions may effectively mediate gestational weight gain and adverse pregnancy outcomes. Whether maternal diet and exercise in pregnancy also benefits offspring body size and composition in infancy is not widely investigated. Further, adherence to interventions in longitudinal studies is often overlooked. Objectives: 1) Determine the effects of a nutrition+exercise intervention compared with standard prenatal care throughout pregnancy on infant anthropometry and body composition 2) Compare the dietary practices between intervention and control groups 3) Create an algorithm to assess intervention adherence Study Design: Maternal diet and physical activity were collected from a subset of women at 12-17, 26-28, 36-38 weeks gestation while enrolled in the Be Healthy in Pregnancy randomized controlled trial. Infant birth size was obtained from hospital records, and anthropometry and body composition outcomes were measured at six months postpartum. Percentile values for anthropometric measures were obtained using population reference growth standards. Diet quality was assessed through food frequency questionnaire, and a novel adherence algorithm was created using step counts from an accelerometer and three-day diet record. Results: For 183 participants of mean age 31 ± 4 years and BMI 25.3 ± 4.7 kg/m2 , infant anthropometry and body composition at birth and six months were similar between intervention and control groups with the exception that intervention infants had significantly higher birth length and a higher proportion categorized above the 97th percentile for reference length measures. In the analysis of healthy dietary practices (N=111) intervention and control participants had similar scores at baseline but only intervention participants improved and maintained their dietary practice scores in mid and late pregnancy. Application of the adherence score incorporating diet and step counts demonstrated increased adherence to the intervention in mid-pregnancy in intervention participants, but this level of adherence was not maintained through the end of pregnancy. Conclusion: In a healthy pregnant cohort, a lifestyle intervention did not significantly impact infant anthropometry or body composition and most measures were within appropriate reference ranges for age and sex. The novel algorithm to measure intervention adherence demonstrated inconsistent compliance across pregnancy in intervention participants, potentially contributing to null findings. / Thesis / Master of Science (MSc) / Excessive weight gain in pregnancy can impact fetal and child growth and health. Diet and exercise modifications during pregnancy may improve weight gain but influence on infant outcomes is unknown. It is important to determine if women actually follow such guidance. Our study showed that infants of women randomized to a diet and exercise program compared to usual prenatal care had similar body size and body composition at birth (except length) and age six months. Women in both treatment groups had similar healthy dietary practices in early pregnancy, but with dietary counselling intervention women improved their diet. However, a unique scoring system developed to measure adherence to diet and exercise revealed that it was difficult for women to follow the guidance provided. Our study provides insights into the association of diet in pregnancy and infant growth in a Canadian population, and a novel approach to measuring ability to follow guidance.

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Prediction of body composition was assessed in thirty-eight female and thirty-seven male random source dogs using in vivo methods of deuterium oxide dilution, subjective and objective morphometry, bioelectrical impedance and ultrasound, either separately or in various combinations. Carcass composition determined by chemical analyses of carcass homogenates served as criterion measures of body composition. Dogs were selected based on gender, body weight and body condition score. Body weight ranged from 7.3 to 34.5 kilograms (kg), subdivided into 4.5 kg increments with 6 female and 6 male dogs per increment. Body condition was categorized as thin, optimum or obese using a defined criteria, body condition scoring system (subjective morphometry) with 12 female and 12 male dogs per body condition category. Selection criteria produced 18 body weight condition groups with 2 female and 2 male dogs per group. One additional male and 2 female dogs were included for economic and ethical reasons. Equations to predict carcass composition from in vivo measurements were derived using standard regression techniques. Influence diagnostics, residual analysis and data splitting were used to validate predictive equations. Predictions from deuterium oxide dilution produced the most precise estimates of body composition. Average standard errors of estimation (SEE) from deuterium equations were 1.3, 1.8, 1.0, and 0.4 percent for percentages of body moisture, fat, protein and ash, respectively, and 0.39, 0.57,0.21 and 0.08 kg for absolute quantities of moisture, fat, protein and ash, respectively. Morphometry produced the most imprecise, but economical, estimates. Average SEE from morphometry equations for proportions were 3.0, 4.0, 1.3, and 0.4 percent, and 0.9, 0.9, 0.3 and 0.07 kg for absolute quantities of moisture, fat, protein and ash, respectively. Subjective morphometry could estimate body fat with an average SEE of 3.4 percent and correctly categorized 75 percent of the dogs. Bioelectrical impedance and ultrasound produced predictions with average SEE intermediate to deuterium and morphometry. Bioelectrical impedance was equivalent to deuterium dilution on the basis of cost per unit improvement in SEE, but ultrasound was not cost effective. / Ph. D.