儿童青少年双生子瘦素遗传度估计及影响因素分析

目的 分析影响儿童青少年瘦素的遗传因素和环境因素,探讨性别、年龄和体质量指数(BMI)的作用,为儿童肥胖早期预防提供依据.方法 选择6～18岁同性别双生子337对,平均年龄(12.3±3.5)岁,其中同卵双生子257对,异卵双生子80对.采用DNA微卫星多态性鉴定卵性.应用Mx结构方程模型分别计算年龄和BMI调整前后瘦素的遗传度,并检验性别、年龄和BMI对于模型的作用.结果 不同性别间身高、体重和瘦素水平差异均有统计学意义(P值均＜0.05).相关分析显示,瘦素水平与性别、年龄和BMI相关(P值均＜0.0l).遗传分析发现,调整前年龄方差在女生中影响较大,而男生则受共同环境方差影响较大.调整后男生特异性性别方差降低,最适模型为ACE(scale)模型.男、女生瘦素遗传模型一致,遗传度为20％.结论 儿童青少年人群中瘦素水平与性别、年龄和BMI相关.瘦素受遗传和环境因素共同影响.调整年龄及BMI后,瘦素遗传度不受性别影响.     

Heritability of body mass index in pre-adolescence, young adulthood and late adulthood

Increased body mass index (BMI) is a worldwide health issue. Individual differences in the susceptibility to increased BMI could be related to genes or environment. We performed a systematic review of genetic studies on BMI in pre-adolescence, young adulthood and late adulthood. We searched PubMed and EMBASE with heritability, body mass index, BMI, weight, height, anthropometry and twins as search terms. Studies reporting intra-pair correlations of healthy twin pairs that were raised together were included. This resulted in the inclusion of 8,179 monozygotic (MZ) and 9,977 dizygotic (DZ) twin pairs from twelve published studies in addition to individual participant data for 629 MZ and 594 DZ pairs from four twin registries. Structural equation modelling with intra-pair twin correlations showed that the heritability of BMI remained high over all age categories ranging from 61% (95% CI 54-64%) to 80% (95% CI 76-81%) for male and female subjects combined, while unique environmental influences increased from 14% (95% CI 13-15%) to 40% (95% CI 37-43%) with increasing age. Heritability of BMI remains consistently high over different age categories. Environmental changes over time do not seem to have as big a relative impact on an individual's weight as previously reported, suggesting a mainly genetic influence on variation in BMI over the years.     

Twin study of genetic and environmental effects on lipid levels

A study of 106 pairs of monozygotic (MZ) and 94 pairs of dizygotic (DZ) twins tested the hypothesis that part of the previously described genetic influence on blood lipid levels can be ascribed to closer similarities among MZ than among DZ twin pairs in environmental factors that affect lipid levels. Participants were adult twin volunteers (age 17-66; 64 male and 136 female pairs) who were selected from the NH & MRC Twin Registry or were respondents to advertisements. They completed a 4-day weighed food diary from which mean nutrient intake was derived. Information on lifestyle and demographic variables was obtained by questionnaire and a nonfasting blood sample was taken for measures of total, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol and the HDL2 and HDL3 subfractions. Height and weight were measured, and body mass index (BMI) was calculated (kg/m2). Estimates of the heritability of sex-adjusted lipid levels were 0.72 for total cholesterol, 0.79 for HDL cholesterol, 0.69 for HDL2, 0.20 for HDL3, 1.06 for LDL cholesterol, and 0.44 for sex-adjusted BMI. In all cases except for HDL3, genetic variance was statistically significant. After adjusting for the effects of environmental variables in three different ways, the estimates of heritability were somewhat lower for total cholesterol, HDL2, and BMI, and those for HDL cholesterol (borderline) and LDL cholesterol (definitely) remained statistically significant but were decreased. A genetic influence on HDL3 was not found. Adjusted heritability estimates obtained from one method of analysis were 0.35 for total cholesterol, 0.49 for HDL, 0.04 for HDL2, -0.34 for HDL3, 0.66 for LDL, and 0.32 for BMI. These results suggest that the assumptions made in the classical twin study approach are not appropriate when examining genetic effects on lipid levels or BMI, or indeed on any biological variable that may be affected by environmental factors that tend to be more similar in MZ twins than in DZ twins. In these circumstances, more complex models may be needed to differentiate between genetic and environmental influences.     

汉族儿童青少年体型遗传的双生子研究

目的分析遗传与环境因素对儿童青少年体型的影响,并探讨其中年龄和性别的作用。方法采用Heath-Carter法对376对6～18岁同性别汉族双生子（同卵双生子245对,异卵双生子131对）的体型三因子进行计算。调整另外两项体型因子后,用Mx软件拟合最佳模型,计算各体型因子的遗传与环境方差组分,分析年龄和性别的作用,并按体格突增分期估算不同发育期各因子的遗传度。结果校正年龄后,男生内、中、外三因子的遗传度分别为0．45,0．80,0．44;女生内、中、外三因子的遗传度分别为0．82,0．79,0．81;男生内因子的遗传度在青春期晚期明显高于前期（t=4．99,P〈0．01）和早期（t=6．16,P〈0．01）,外因子的遗传度在青春期晚期明显低于前期（t=3．35,P〈0．01）和早期（t=4．12,P〈0．01）;女生内因子（t=2．77,P〈0．01）、中因子（t=2．08,P〈0．05）的遗传度均为青春期前期明显高于早期。结论遗传因素对女生体型的影响明显高于男生,尤以内因子和外因子最为明显,男生中因子主要受遗传因素影响,内、外因子受环境因素影响较大。不同发育阶段对体型各因子遗传度的影响应引起重视。     

Differences in Nutritional Intake,Total Body Fat,and BMI Score between Twins

The present study aimed to investigate the coincidence of obesity and nutritional intake in monozygotic twins compared to dizygotic twins. The data from the Korean Genome and Epidemiology Study (KoGES) from 2005 through 2014 were analyzed. Participants ≥ 20 years old were enrolled. The 1006 monozygotic twins and 238 dizygotic twins were analyzed for differences in self-reported nutritional intake, total body fat, and body mass index (BMI) using a linear regression model. The estimated values (EV) with 95% confidence intervals (95% CI) of the difference in dietary intake, total body fat, and BMI score were calculated. The monozygotic twin group and the dizygotic twin group showed similar differences in nutritional intake, DEXA fat, and BMI (all p > 0.05). The differences in nutritional intake of total calories and carbohydrates were lower in the monozygotic twin group than in the dizygotic twin group (all p < 0.05). The differences in total body fat were lower in monozygotic twins than in dizygotic twins (adjusted EV = 2427.86 g, 95% CI = 1777.19–3078.53 and adjusted EV = 1.90%, 95% CI = 1.33–2.46). Monozygotic twins had more similar dietary habits for total calories and carbohydrate intake. Other nutritional factors did not show differential similarity between monozygotic and dizygotic twins. Total body fat was more concordant in monozygotic twins.     

Cardiorespiratory fitness and dietary intake in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence study

The present study investigated the association between cardiorespiratory fitness (CRF) and dietary intake in European adolescents. The study comprised 1492 adolescents (770 females) from eight European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study. CRF was assessed by the 20 m shuttle run test. Adolescents were grouped into low and high CRF levels according to the FITNESSGRAM Standards. Dietary intake was self-registered by the adolescents using a computer-based tool for 24 h dietary recalls (HELENA-Dietary Assessment Tool) on two non-consecutive days. Weight and height were measured, and BMI was calculated. Higher CRF was associated with higher total energy intake in boys (P = 0·003). No association was found between CRF and macronutrient intake (as percentage of energy), yet some positive associations were found with daily intake of bread/cereals in boys and dairy products in both boys and girls (all P < 0·003), regardless of centre, age and BMI. CRF was inversely related to sweetened beverage consumption in girls. These findings were overall consistent when CRF was analysed according to the FITNESSGRAM categories (high/low CRF). A high CRF was not related to compliance with dietary recommendations, except for sweetened beverages in girls (P = 0·002). In conclusion, a high CRF is associated with a higher intake of dairy products and bread/cereals, and a lower consumption of sweetened beverages, regardless of centre, age and BMI. The present findings contribute to the understanding of the relationships between dietary factors and physiological health indicators such as CRF.     

Lifestyle and blood pressure levels in male twins in Utah

Healthy male monozygotic (MZ) and dizygotic (DZ) twin pairs (MZ pairs = 77; DZ pairs = 88) were studied to assess the effect of dietary intake, physical activity, physical fitness, body mass index (BMI), sum of the triceps and subscapular skinfold measurements, alcohol and caffeine consumption, and smoking patterns on blood pressure. Data on physical activity, detailed dietary intake, medical history, and demographics were obtained from a questionnaire. A bicycle ergometer was used to estimate level of fitness; other medical information was ascertained from physical examination. After normalizing the study variables, intraclass correlations for BMI and the sum of the triceps and subscapular skinfold measurements were higher in MZ than in DZ twin pairs (BMI: MZ r = 0.76, DZ r = 0.48; skinfolds: MZ r = 0.73, DZ r = 0.28), as were VO2max(MZ r = 0.63, DZ r = 0.25) and post-bike heart rate (MZ r = 0.69, DZ r = 0.19). Both systolic (SBP) and diastolic blood pressure (DBP) had high heritability estimates (SBP = 0.60, and DBP = 0.66). Using factor analysis, four major lifestyle factors were identified and categorized as: 1) dietary intake; 2) a factor heavily weighted by cigarette smoking, alcohol and caffeine consumption; 3) fatness; 4) physical activity and physical fitness. Adjustment for these factors did not alter heritability estimates for either SBP or DBP.     

Heritability of blood pressure in 7- to 12-year-old Chinese twins, with special reference to body size effects

Systolic and diastolic blood pressures and body-size indices such as body height, body weight, sitting height, chest circumference, skinfold thickness, and body mass index (BMI) were assessed in 110 pairs of like-sex Chinese twins (75 monozygotic and 35 dizygotic) aged 7-12 years. Significant correlations of blood pressure with body-size indices were found. Prior to adjusting for body-size effects, three twin methods yielded low heritability estimates for both systolic (0.32-0.41) and diastolic (0.32-0.51) pressures. Adjusting systolic pressure for body height and BMI via multiple regression nearly halved heritability estimates, but adjusting diastolic pressure for body height and skinfold thickness only changed the estimates slightly.     

成年双生子血尿酸遗传度研究

目的 用双生子研究方法 对成年人血尿酸的遗传度进行估计.方法 从青岛双生子库募集成年双生子.测量身高、体重和血尿酸.相同性别的双生子采用16个多态标记进行卵型鉴定.通过校正年龄、性别和BMI,来构建结构方程模型估计遗传度.结果 共收集687对双生子数据,其中同卵双生子420对,异卵双生子267对.经平方根转换后,男性血尿酸水平(17.47±1.91)略高于女性(15.22±1.70)(P＜0.0001),通过校正年龄、性别和BMI后双生子血尿酸的组内相关系数分别为,同卵双生子0.70、异卵双生子0.40.运用性别限制模型进行拟合,最佳模型AE模型,加性别遗传因素和特殊环境因素共同作用血尿酸的水平.血尿酸的遗传度为70.5%(95%CI:65.9～74.6),特殊环境因素占29.5%(95%CI:25.4～34.2).结论 遗传因素是影响样本双生子血尿酸水平的主要因素.     

Genetic and environmental influences on body-fat measures among African-American twins

OBJECTIVE: To investigate the genetic and environmental influences on body-fat measures including waist circumference (WC), waist-to-hip ratio (WHR), and body mass index (BMI) among African-American men and women. RESEARCH METHODS AND PROCEDURES: Measurements were taken as part of the Carolina African American Twin Study of Aging. This sample currently comprises 146 same-sex African-American twins with an average age of 50 years (range, 22 to 88 years). This analysis included 26 monozygotic and 29 dizygotic men and 45 monozygotic and 46 dizygotic women. Maximum likelihood quantitative genetic analysis was used. RESULTS: In men, additive genetic effects accounted for 77% of the variance in WC, 59% in WHR, and 89% in BMI. In women, additive genetic effects accounted for 76% of the variance in WC, 56% in WHR, and 73% in BMI. The remaining variance in both men and women was attributed to unique environmental effects (WC, 21%; WHR, 36%; BMI, 11% in men and WC, 22%; WHR, 38%; BMI, 27% in women) and age (WC, 2%; WHR, 5% in men and WC, 2%; WHR, 6% in women). When BMI was controlled in the analysis of WC and WHR, it accounted for a portion of the genetic and environmental variance in WHR and over one-half of the genetic and environmental variance in WC. DISCUSSION: There are both genetic and environmental influences on WC, WHR, and BMI, and independent of BMI, there are genetic and environmental effects on WC and WHR among both genders. The results from this African-American twin sample are similar to findings among white twin samples.     

学龄前双生子儿童围度指标的遗传学研究

【目的】 分析遗传和环境因素对学龄前双生子儿童围度发育的影响及其性别和年龄因素的作用。 【方法】 对3~6岁101对双生子(同卵双生子42对、同性别异卵双生子30对,异性别异卵双生子29对)的头围、胸围、腰围、臀围、上臂围及小腿围进行测量;对测量结果进行结构方程模型拟合,并估算各指标遗传度。 【结果】 最佳模型除头围为AES外,其他各指标均为ACES模型,遗传、环境、年龄因素对各指标均有不同程度影响。校正年龄后,各指标遗传度为:头围(男0.83,女0.75)、胸围(男0.56,女0.43)、腰围(男0.77,女0.72)、臀围(男0.49,女0.63)、上臂围(男0.58,女0.36)、小腿围(男0.82,女0.76)。 【结论】 学龄前儿童头围、腰围、小腿围主要受遗传因素影响,胸围、臀围、上臂围受环境因素影响相对较大。     

Influence of genetic and environmental factors on the immunogenicity of Hib vaccine in Gambian twins

The differences in incidence rates of Haemophilus influenzae type b disease and the variation in Hib conjugate vaccine efficacy achieved among different ethnic groups suggest genetic influences on the immune response to Hib vaccine. The serum anti-PRP antibody concentration of 43 monozygotic (MZ) and 147 dizygotic (DZ) twin pairs in the Gambia was measured using a standardised Hib ELISA. Intrapair correlations for MZ and DZ twin pairs were compared and heritability in antibody responses to Hib conjugate vaccine was estimated to be 51% (95% CI: 32-66%), indicating a significant genetic contribution in the response. We conclude that genetic factors may be involved in the variation in immune response to Hib vaccine observed in different populations and may contribute to cases of vaccine failure.     

Genetic effects on weight change and food intake in Swedish adult twins

BACKGROUND: Obesity is influenced by genetic and environmental factors. Additionally, synergistic effects of genes and environments may be important in the development of obesity. OBJECTIVE: The aim of this study was to test for genetic effects on food consumption frequency, food preferences, and their interaction with subsequent weight gain. DESIGN: Complete data on the frequencies of consumption of 11 foods typical of the Swedish diet were available for 98 monozygotic and 176 dizygotic twin pairs aged 25-59 y who are part of the Swedish Twin Registry. The data were collected in 1973 as part of a questionnaire study. Body mass index was measured in 1973 and again in 1984. RESULTS: There was some evidence that genetic effects influenced the frequency of intake of some foods. Similarity among monozygotic twins exceeded that among dizygotic twins for intake of flour and grain products and fruit in men and women, intake of milk in men, and intake of vegetables and rice in women, suggesting that genes influence preferences for these foods. Analyses conducted for twins reared together and apart also suggested greater monozygotic than dizygotic correlations, but cross-twin, cross-trait correlations were all insignificant, suggesting that the genes that affect consumption frequencies are not responsible for mediating the relation between the frequency of intake and weight change. CONCLUSIONS: Genetic effects and the frequency of intake are independently related to change in body mass index. However, there was no suggestion of differential genetic effects on weight gain that were dependent on the consumption frequency of the foods studied.     

Seasonal and gender differences of beverage consumption in elementary school students

The purpose of this study was to compare the beverage consumption by gender and season in elementary school children and to investigate the role of beverage consumption patterns on their daily nutrient intakes and BMIs. Beverage consumption and dietary energy intake in 160 elementary school students in the Gyeongnam area were measured by a beverage frequency and quantity questionnaire and three 24-hour dietary recalls during winter and summer. The number of drinking moments per month, the amounts of beverage per day, and the energy from beverage consumption were not different between winter and summer. In summer, the contribution of energy from sweetened beverage to the daily energy intake in girls accounted for 13.5% which was significantly higher compared to 7.7% in boys. In girls, the consumption of health beverage showed a significant correlation with various nutrient intakes in winter. Meanwhile, the sweetened beverage intake was negatively correlated with energy, protein, vitamin A and niacin intake in summer. Consumption of most of the beverages, including sweetened beverages, were not related with BMI in both sexes and both seasons, except functional drinks which were related with BMI in boys in winter.     

Comparison of the Concordance of Cardiometabolic Diseases and Physical and Laboratory Examination Findings between Monozygotic and Dizygotic Korean Adult Twins: A Cross-Sectional Study Using KoGES HTS Data

This study investigated the contribution of genetic and environmental factors to cardiometabolic diseases (CMDs) by comparing disease concordance in monozygotic and dizygotic twins. This cross-sectional study analyzed 1294 (1040 monozygotic and 254 dizygotic) twin pairs (>20 years) based on the Korean Genome and Epidemiology Study data (2005–2014). The odds ratios of disease concordance were calculated using binomial and multinomial logistic regression models. The occurrence of CMDs (hypertension, hyperlipidemia, type 2 diabetes, cerebral stroke, transient ischemic attack, and ischemic heart disease) and related physical and laboratory levels did not differ between the monozygotic and dizygotic twin groups. The odds for concordance of the presence/absence of CMDs and the likelihood of incident CMD within monozygotic twins were comparable to that of dizygotic twins. The absolute differences in hemoglobin A1c, insulin, low- and high-density lipoprotein cholesterol, total cholesterol, triglycerides, and systolic blood pressure were lower in monozygotic twins than in dizygotic twins. Absolute differences in fasting glucose and diastolic blood pressure did not differ between groups. Although baseline levels of several laboratory parameters related to CMD showed a strong likelihood of heritability in monozygotic twins, CMD phenotype appears to be largely affected by environmental factors.     

双生子的血清脂质和脂蛋白遗传度及影响因素分析

目的　分析儿童、青少年的血脂指标遗传度及影响因素。方法　选择 5～ 19岁双生子2 36对 ,平均年龄 (11 2± 3 4 )岁 ,其中同卵双生子 14 3对 ,异卵双生子 93对。在DNA卵性鉴定基础上 ,以组内相关系数法及Falconer公式计算调整年龄性别前后的遗传度 ,偏态数据进行对数转换 ;校正年龄性别 ,分析相关体格、生化指标对血脂的影响。结果　同卵与异卵双生子间甘油三酯对内方差及相关系数的差异均无显著性 ;总胆固醇、高密度脂蛋白胆固醇 (HDL C)、低密度脂蛋白胆固醇 (LDL C)和脂蛋白 (a)对内方差及相关系数的差异有显著性 ,遗传度估计值分别为 0 5 6、0 5 5、0 4 9和 0 5 8,调整年龄性别后各指标估计遗传度分别为 0 6 3、0 6 3、0 5 5和 0 6 4。总胆固醇、HDL C、LDL C和脂蛋白(a)与年龄呈负相关 ;女孩的总胆固醇、HDL C、LDL C稍高于男孩。校正年龄性别后除脂蛋白 (a)外各血脂指标多数与体重指数、体脂率及培利迪西指数相关 ,与血压、血糖和血钙等也有相关性。结论　总胆固醇、HDL C、LDL C和脂蛋白 (a)受遗传因素影响较大 ,而甘油三酯主要受环境因素影响。儿童的血脂水平受年龄和性别的影响 ,与反映体脂和机体营养发育的指标相关。     

Heritability of symptom domains in otitis media: a longitudinal study of 1,373 twin pairs

Research on risk factors and pathogenesis of otitis media has emphasized the environment, but previous twin studies suggest a strong genetic component. In those studies, no attempt was made to differentiate the role of initial acute infection from the chronic airway blockage that frequently accompanies persistent effusion. The authors estimated genetic and environmental determination of both of these aspects of otitis media histories at three time points. A large and representative subset of a total population cohort of all twins born in England and Wales in 1994, was studied prospectively at ages 2, 3, and 4 years (monozygotic, n = 715; dizygotic, n = 658). For the total symptom score, the estimated heritabilities at ages 2, 3, and 4 years were 0.49, 0.66, and 0.71, respectively. All correlations for the total score found in monozygotic twins were about 0.9, but correlations were lower for dizygotic twins (p < 0.65). Shared environmental influences declined in importance over time (0.41, 0.22, and 0.16 at ages 2, 3, and 4 years, respectively). No gender differences were found in parameter estimates. Symptoms of acute infections showed lower heritability (0.57 on average) and higher shared environment (0.18) than did chronic airway blockage (0.72 heritability and 0.10 shared environment). The strong genetic component, which this study confirms, is not unitary but distributes differently across the phenotypic aspects of otitis media and probably across pathogenetic stage.     

汉族双生子儿童体格发育指标的遗传效应

目的 分析儿童体格发育指标的遗传度及其影响因素。方法 于2004年6至10月测量116对6-12岁同性别汉族双生子（同卵双生子67对、异卵双生子49对）的身高、体重、坐高、胸围、肩宽和骨盆宽,计算体重指数,调整年龄后用组内相关系数法计算各指标遗传度。结果 各指标组内相关系数均为同卵双生子大于异卵双生子;男女性身高的遗传度分别为0．89和0．87,体重的遗传度分别为0．88和0．74,体重指数的遗传度分别为0．73和0．72,坐高的遗传度分别为0．87和0．86,胸围的遗传度分别为0．88和0．62,肩宽的遗传度分别为0．78和0．56,骨盆宽的遗传度分别为0．73和0．59,男女性的身高、坐高和体重指数的遗传度差异无统计学意义,其余各指标的遗传度均男性高于女性。结论 遗传因素对儿童的体格发育特征起主要作用,体重、胸围、肩宽和骨盆宽的遗传度存在性别差异,女性比男性更易受环境因素影响。     

Comparative study of the consumption of cariogenic food in monozygotic and same-sex dizygotic twins

The eating habits of the 111 monozygotic and 67 like-sexed dizygotic twins were compared with respect to cariogenic foods. The food habits were recorded using a seven-day dietary history with the weekly frequency of the cariogenic foods examined. The biometrical analysis showed that the eating habits of the monozygotic pairs were more similar than that of the dizygotic twin pairs. The differences were statistically significant. Based on these findings, it seems that genetic factors play a role in the development of the food habits.     

Iron intake and dietary sources of iron in Flemish adolescents

OBJECTIVE: To investigate the dietary iron intake and food sources of iron in Flemish adolescents. DESIGN: Cross-sectional survey; dietary assessment method: a 7-day estimated food record. SETTING: Private and public secondary schools in Ghent, a city in the Dutch-speaking part of Belgium. SUBJECTS: A total of 341 adolescents (129 boys and 212 girls), 13-18 y, randomly selected by a multistage clustered sampling technique. RESULTS: The mean total iron intake (s.d.) for boys was 13.4 (+/- 2.91) mg/day and for girls 10.1 (+/- 2.79) mg/day. A proportion of 38.8% of the boys and 99.5% of the girls had a mean total iron intake below the Belgian Recommended Dietary Allowance and 3.1% of the boys and 71.2% of the girls below the British Estimated Average Requirement. When bioavailable iron intake is considered, 84.5% of the boys and only 16.5% of the girls met the age-specific requirement. The food groups with the highest mean proportional contribution to total iron intake in both males and females were bread, meat and meat products, cereals and potatoes. A comparison of adolescents from the highest tertile of iron intake (mg/day) with adolescents from the lowest tertile showed a significantly higher energy-adjusted intake of brown bread and a significantly lower intake of soft drinks in the former group in both boys and girls. A significantly higher energy-adjusted intake of breakfast cereals in adolescents of the highest tertile than those of the lowest tertile was seen in girls only. Analyses in consumers only did not change this overall picture. CONCLUSIONS: One can conclude that the mean iron intake of Flemish girls is considerably lower than the current recommendations. An increased iron intake in this subgroup of the population is therefore advisable.