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- Genetic regulation of body size and morphology in children: a twin study of 22 anthropometric traitsPublication . Silventoinen, Karri; Maia, José; Li, Weilong; Sund, Reijo; Gouveia, Élvio R.; Antunes, António; Marques, Gonçalo; Thomis, Martine; Jelenkovic, Aline; Kaprio, Jaakko; Freitas, Duarte Luís deAnthropometric measures show high heritability, and genetic correlations have been found between obesity related traits. However, we lack a comprehensive analysis of the genetic background of human body morphology using detailed anthropometric measures. METHODS: Height, weight, 7 skinfold thicknesses, 7 body circumferences and 4 body diameters (skeletal breaths) were measured in 214 pairs of twin children aged 3–18 years (87 monozygotic pairs) in the Autonomous Region of Madeira, Portugal. Factor analysis (Varimax rotation) was used to analyze the underlying structure of body physique. Genetic twin modeling was used to estimate genetic and environmental contributions to the variation and co-variation of the anthropometric traits. RESULTS: Together, two factors explained 80% of the variation of all 22 anthropometric traits in boys and 73% in girls. Obesity measures (body mass index, skinfold thickness measures, as well as waist and hip circumferences) and limb circumferences loaded most strongly on the first factor, whereas height and body diameters loaded especially on the second factor. These factors as well as all anthropometric measures showed high heritability (80% or more for most of the traits), whereas the rest of the variation was explained by environmental factors not shared by co-twins. Obesity measures showed high genetic correlations (0.75–0.98). Height showed the highest genetic correlations with body diameter measures (0.58–0.76). Correlations between environmental factors not shared by co-twins were weaker than the genetic correlations but still substantial. The correlation patterns were roughly similar in boys and girls. CONCLUSIONS: Our results show high genetic correlations underlying the human body physique, suggesting that there are sets of genes widely affecting anthropometric traits. Better knowledge of these genetic variants can help to understand the development of obesity and other features of the human physique.
- Genetics of somatotype and physical fitness in children and adolescentsPublication . Silventoinen, Karri; Maia, José; Jelenkovic, Aline; Pereira, Sara; Gouveia, Élvio; Antunes, António; Thomis, Martine; Lefevre, Johan; Kaprio, Jaakko; Freitas, DuarteObjectives: To analyze the influence of genetic and environmental factors on the variation in somatotype, physical fitness, and their mutual associations. Methods: Twins from 214 pairs (87 monozygotic) of the Autonomous Region of Madeira, Portugal, from 3 to 18 years of age (51% girls) were assessed in anthropometry and physical fitness tests. We estimated endomorphy, meso morphy, and ectomorphy based on anthropometric measures and physical fit ness using the Eurofit test battery. Two age categories were analyzed: children (3-11 years) and adolescents (12-18 years). Genetic and environmental varia tions were estimated using quantitative genetic twin modeling. Results: No genetic sex differences were found, thus boys and girls were pooled in all genetic analyses. Heritability estimates were high for somatotype (a2 = 0.80-0.93), physical fitness traits (a2 = 0.67-0.83), and largely similar in children and adolescents. Positive correlations were found for ectomorphy with motor ability and cardiorespiratory endurance as well as for endomorphy and mesomorphy with muscular strength (r = 0.25-0.37). In contrast, negative asso ciations were found for ectomorphy with muscular strength, as well as for endomorphy and mesomorphy with motor ability and cardiorespiratory endurance (−0.46 to −0.26). Twin modeling indicated that these associations were explained mostly by genetic factors in common to the two associated traits (84% or more). Conclusions: Associations between somatotype and physical fitness tests are mainly explained by common genetic background in children and adolescents. Therefore, interventions in youth should consider that a child's performance in physical fitness tests partly reflects their inherited physique.
- The genetic background of metabolic trait clusters in children and adolescentsPublication . Silventoinen, Karri; Gouveia, Élvio; Jelenkovic, Aline; Maia, José; Antunes, António M.; Carvalho, Miguel Â. A. Pinheiro de; Brehm, António M.; Thomis, Martine; Lefevre, Johan; Kaprio, Jaakko; Freitas, DuarteBackground: It is well known that the metabolic risk factors of cardiovascular diseases are correlated, but the background of this clustering in children is more poorly known than in adults. Thus, we studied the contribution of genetic and environmental factors to the clustering of metabolic traits in childhood and adolescence. Methods: Nine metabolic traits were measured in 214 complete twin pairs aged 3 to 18 years in the Autonomous Region of Madeira, Portugal, in 2007 and 2008. The variation of and covariations between the traits were decomposed into genetic and environmental components by using classical genetic twin modeling. Results: A model including additive genetic and environmental factors unique for each twin individual explained the variation of the metabolic factors well. Under this model, the heritability estimates varied from 0.47 (systolic blood pressure in children under 12 years of age) to 0.91 (HDL cholesterol in adolescents 12 years of age or older). The most systematic correlations were found between adiposity (body mass index and waist circumference) and blood lipids (HDL cholesterol, LDL cholesterol and triglycerides), as well as blood pressure. These correlations were mainly explained by common genetic factors. Conclusions: Our results suggest that obesity, in particular, is behind the clustering of metabolic factors in children and adolescents. Both general and abdominal obesity partly share the same genetic background as blood lipids and blood pressure. Obesity prevention already in childhood is important in reducing the risk of metabolic diseases in adulthood.
- Regional variation in growth status. The Peruvian health and optimist growth studyPublication . Bustamante, Alcibiades; Santos, Carla; Pereira, Sara; Freitas, Duarte; Katzmarzyk, Peter T.; Maia, JoséObjective: This study aims to (1) investigate differences in weight, body mass index (BMI), and waist circumference (WC) among Peruvian children and ado lescents living in three areas located at different altitudes; (2) compare age and sex-specific height, weight, and BMI within each site with US reference data. Methods: We sampled 8753 subjects (4130 boys), aged 4 to 17 years from sea level, rainforest, and high-altitude. Height, weight, and WC were measured and BMI was calculated. Analysis of variance was used to compare variables across geographic regions, and the Hoff and Blackburn procedure was used to compare the Peruvian results with US reference data. Results: Participants living at sea level were taller, heavier, had greater BMI and WC relative to those living at high-altitude and in the rainforest. Peruvian schoolchildren of both sexes from the three geographical areas were shorter and lighter than their American peers. Boys and girls living in the rainforest and at high-altitude had lower BMI, whereas WC values of American schoolchildren are higher than those of the Peruvian children by age and gender. Conclusions: Peruvians living at different altitudes differ in their growth indi cators (height, weight, BMI, and WC), with significant differences between those living at sea level relative to their peers from other regions. Further, Peruvian schoolchildren of both sexes from the three geographical areas signif icantly differ from their US counterparts
- Physical fitness spurts in pre-adolescent boys and girls: Timing, intensity and sequencingPublication . Pereira, Sara; Santos, Carla; Tani, Go; Freitas, Duarte; Garbeloto, Fernando; Guimarães, Eduardo; Robinson, Leah E.; Baxter-Jones, Adam; Katzmarzyk, Peter T.; Maia, JoséWe aim to (1) estimate age of attainment of the peak mid-growth spurt in stature (age-at-peak MGS) in pre-adolescent boys and girls; (2) identify the timing, intensity, and sequences of physical fitness (PF) spurts aligned by the age-at-peak MGS; and (3) identify any sex differences in PF spurts aligned by age-at peak MGS. The sample included 180 Portuguese children (90 girls) aged 6 to 10 years at study entry who were followed annually for 4 years. Height, health-, and performance-related PF were assessed. Age-at peak MGS and PF spurts were estimated using a non-smooth mathematical procedure. Boys’ and girls’ age-at-peak MGS occurred at 7.8 ± 0.47 years and 8.0 ± 0.72 years, respectively. PF spurts’ timing aligned by age-at-peak MGS were as follows: (1) before age-at-peak MGS: boys – static strength, aerobic capacity, explosive leg strength, and flexibility; girls – speed, agility, aerobic capacity, and upper body strength; (2) coincident with age-at-peak MGS: girls – explosive leg strength and flexibility; (3) after age-at-peak MGS: boys – abdominal strength, upper body strength, agility, and speed; girls – abdominal strength and static strength. Boys and girls attained their MGS at relatively similar ages. However, the timing and sequences of PF spurts, aligned on age-at-MGS, were different between boys and girls.
- Biological and environmental determinants of 12-minute run performance in youthPublication . Freitas, Duarte; Maia, José; Stasinopoulos, Mikis; Gouveia, Élvio Rúbio; Antunes, António M.; Thomis, Martine; Lefevre, Johan; Claessens, Albrecht; Hedeker, Donald; Malina, Robert M.Background: The 12-minute run is a commonly used indicator of cardiorespiratory fitness in youth. Variation in growth and maturity status as potential correlates of test performance has not been systematically addressed. Aim: To evaluate biological and environmental determinants of 12-minute run performance in Portuguese youth aged 7–17years. Subjects and methods: Mixed-longitudinal samples of 187 boys and 142 girls were surveyed in 1996, 1997 and 1998. The 12-minute run was the indicator of cardiorespiratory fitness. Height, body mass and five skinfolds were measured and skeletal maturity was assessed. Physical activity, socioeconomic status and area of residencewere obtainedwitha questionnaire. Multi-level modelling was used fortheanalysis. Results: Chronological age and sum of five skinfolds were significant predictors of 12-minute run performance. Older boys and girls ran longer distances than younger peers, while high levels of subcutaneous fat were associated with shorter running distances. Rural boys were more proficient in the 12-minute run than urban peers. Skeletal maturity, height, body mass index, physical activity and socioeconomic status were not significant predictors of 12-minute run performances. Conclusions: Age and sum of skinfolds in both sexes and rural residence in boys are significant predictors of 12-minute run performance in Portuguese youth.
- Motor performance, body fatness and environmental factors in preschool childrenPublication . Antunes, António M; Freitas, Duarte L.; Maia, José; Hedeker, Donald; Gouveia, Élvio R; Thomis, Martine; Lefevre, Johan; Barnett, Lisa MThe first aim of this study was to investigate the relationship between motor performance and body fatness among 3- to 5-year-old children. The second aim was to assess whether this relationship works similarly for boys and girls. We also investigated whether socioeconomic status (SES) and geographical area when children are aged 3 years old predicts the motor performance of 4 and 5-yr-old children. Motor performance was assessed through the Preschool Test Battery, while body fatness was estimated through body mass index (BMI). SES and geographical area were assessed via parent proxy-report questionnaires. BMI was negatively associated with standing long jump. The association of BMI and motor performance was not statistically different for boys and girls. Children from low SES performed better than high SES peers in tennis ball throw for distance. Rural children were better performers than urban peers in standing long jump. Rural area at baseline was also predictor of standing long jump and tennis ball throw for distance at time 1 and 2. In conclusion, BMI had a negative association with standing long jump and the relationship of BMI with all motor tests was similar for boys and girls. SES and rural area were predictors of motor performance.