3～6岁双生子体型遗传分析

目的 分析3～6岁幼儿体型各因子的遗传度,探讨遗传与环境因素对其体型发育的影响.方法 采用Heath-Carter体型法对72对3～6岁同性别双生子[同卵双生子(MZ)42对,异卵双生子(DZ)30对]的体型进行分析,用Holzinger公式估算体型各因子遗传度.结果 二维空间的体型离散距离(SDD)和三维空间体型位置距离(SAD)显示,MZ的体型较DZ更为接近;体型各因子对间方差在2类双生子间均无明显差异,中因子和外因子的对内方差DZ均明显大于MZ、组内相关系数MZ均明显大于DZ;内、中、外3个因子的遗传度分别为0.38、0.67、0.73.结论 遗传与环境因素对3～6岁幼儿体型发育均有一定影响,内因子主要受环境影响,中、外因子受遗传因素影响较大.     

中国双生子人群2型糖尿病分布特征

目的描述中国双生子登记系统(CNTR)双生子的2型糖尿病分布特征, 为揭示遗传和环境因素对2型糖尿病的影响提供线索和依据。方法 CNTR 2010-2018年项目登记的所有双生子中, 纳入≥30岁且有完整登记信息的18 855对双生子作为研究对象。采用随机效应模型描述2型糖尿病的人群、地区分布特征以及对内一致性的分布。结果研究对象年龄(42.8±10.2)岁, 同卵双生子(MZ)10 339对, 异卵双生子(DZ)8 516对。全人群中2型糖尿病报告患病率为2.2%, MZ和DZ报告患病率差异无统计学意义。双生子对内分析发现2型糖尿病MZ同病率为38.2%, DZ为16.0%, 差异有统计学意义(P<0.001), 在不同性别、年龄和地区中MZ同病率均大于DZ(P<0.05)。进一步分层分析, 在北方, 仅在<60岁人群中发现MZ同病率大于DZ(P<0.05);而南方, ≥60岁男性MZ同病率也大于DZ(P<0.05)。结论本研究的双生子人群2型糖尿病报告患病率低于一般人群, 在不同性别、年龄和地区中均提示遗传因素在2型糖尿病中起作用, 但其作用大小可能不...     

恒牙列拥挤的双生子研究

目的 通过双生子研究遗传和环境因素对恒牙列拥挤形成所起的作用，以进一步研究恒牙列拥挤的影响因素。方法 以48对双生子作为研究对象，应用卵型鉴定技术分为单卵双生子组（MZ）和二卵双生子组（DZ），采取牙[牙合]石膏模型并进行测量，获取牙齿近远中径大小、牙弓弧长及牙列拥挤度等数据；采用Holzinger经典双生子法计算遗传度。结果 同卵与二卵双生于牙齿近远中径的平均值差别无统计学意义。说明牙齿近远中径在同卵．二卵双生子样本中平均水平接近。上下颌牙量遗传度较高。上颌为69．97％，下颌为75．73％；上颌牙弓弧长的遗传度（71．26％）明显高于下颌（31．33％）；单卵双生子和二卵双生子上下颌牙齿的拥挤度的对内相关系数较为接近，二卵双生子略低。遗传度很低，上颌为4．73％，下颌为10．3％。结论 上下颌牙量大小和上颌牙弓弧长受较强遗传控制。下颌牙弓弧长受弱遗传控制，恒牙列拥挤度遗传度很低，受环境因素影响较大。     

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。     

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.     

遗传与环境因素对双生姊妹性激素影响

目的探讨女性青春期发育前后血清雌二醇（E2）和睾酮（T）的变化趋势．评价遗传与环境因素相对效应。方法以学校登记为基础募集6～18岁女性双生子180对，其中同卵双生子（MZ）132对，异卵双生子（DZ）48对，按Tanner标准进行青春发育分期，放免法测定空腹血清雌二醇（E2）和睾酮（T）浓度。结果血清E2和T浓度随青春期进程而增高，Tanner Ⅳ期达高峰．Tanner Ⅴ期略有下降；遗传效应分析显示。双生子血清E2和T偶内平均差、偶内方差为MZ〈DZ（P〈0．05）．组内相关系数为MZ〉DZ；表型方差中归因于加性遗传因素的部分分别为40％（E2）和47％（T）；分期估计遗传度显示E2和T均为已来潮组遗传度高于乳房未发育组和未来潮组。结论青春期女性血清E2和T同时受遗传和环境因素的影响。月经来潮后遗传因素的作用显著。     

男性儿童青少年血清Apelin遗传度及影响因素双生子研究

利用双生子研究分析影响男性儿童青少年血清Apelin的遗传和环境因素,为探讨年龄、体质量指数(BMI)和肥胖在其中的作用提供依据.方法 选择7~18岁男性双生子162名,平均年龄(12.2±3.7)岁,其中同卵双生子100名,异卵双生子62名.利用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、BMI及肥胖调整前后Apelin的遗传度,并分析年龄、BMI和肥胖对Apelin的影响.结果 Apelin水平与年龄呈正相关,肥胖组男童Apelin水平低于正常组(P<0.05).Apelin的遗传度为41%,共同环境方差和独特环境方差分别占37%和22%.调整年龄、BMI及肥胖后,遗传方差比例降低.结论 男性儿童青少年Apelin水平与年龄、肥胖度相关.Apelin受遗传和环境因素的共同影响.     

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。     

双生子A型人格与高血压及血生化指标研究

目的 了解双生子A型人格与高血压及血液生化指标的关系。方法 利用遗传流行病学方法对青岛市89对24岁以上双生子(同卵55对，异卵34对)进行调查。并进行A型人格测试，以比较同卵与异卵双生于A型人格得分的相关程度、A型人格及血压的一致性。推测遗传与环境因素对A型人格的影响，A型人格与高血压的关系，并探讨血液生化指标与A型人格的关系。结果 经KAPPA一致性检验，同卵(MZ)双生子之间A型人格存在着显的一致性(P＜0．001)，而异卵(DZ)双生子之间的一致性无显性差异(P＝0．802)。同时，MZ双生子之间A型人格和血压也存在显的一致性(P＜0．001)，而DZ双生子之间A型人格和血压无明显一致性(P＝0．102)。有A型人格的双生子血压的收缩压明显高于非A型人格的双生子(P＜0．05)。许多生化指标与A型人格因素相关，但是所计算出的相关系数大都小于0．30，属于弱相关。结论 MZ双生子A型人格及高血压之间存在着显的一致性，而这种一致性在DZ双生子表现不明显。A型人格是高血压的危险因素之一。A型人格与所研究血液基本生化指标之间相关较弱。     

青岛市6～18岁女性双生子血清硫酸脱氢表雄酮水平的研究

目的探讨青春期女性血清硫酸脱氢表雄酮(DHEAS)的变化趋势,估计遗传与环境因素的相对效应。方法以学校登记为基础募集青岛市6~18岁女性双生子180对,其中同卵双生子(MZ)132对,异卵双生子(DZ)48对,按Tanner标准进行青春发育分期,放免法测定空腹血清DHEAS浓度。结果青春期女生血清DHEAS浓度随年龄增长和青春期进程而增高,Tanner IV期达高峰,Tanner V期略有下降;遗传效应分析显示血清DHEAS浓度偶内平均差、偶内方差为MZDZ;遗传度为0.65,分期估计遗传度分别为乳房未发育组0.92,乳房发育未来潮组0.73,已潮组0.67。结论青春期女性血清DHEAS受遗传因素的控制较强,尤其乳房发育前肾上腺功能初现期。提示在与肾上腺功能初现有关的内分泌失调性疾病的发病中遗传因素可能起重要的作用。     

青春前期双生子血清骨碱性磷酸酶活性测定及遗传度分析

目的 通过对青春前期双生子血清骨碱性磷酸酶(bone alkaline phosphatase,BALP)活性的测定,分析血清BALP活性的遗传度,评价特定人群钙的缺乏状况和机体对钙的需求情况.方法 调查9～16岁双生子73对,利用骨源性碱性磷酸酶试剂盒进行血清BALP活性测定.在DNA卵型鉴定基础上.以组内相关系数法及Christian遗传度计算公式分析血清BALP活性的遗传度. 结果 经卵型鉴定,73对双生子中同卵双生子34对,异卵双生子39对;BALP>250 U/L的人占43.1%,BALP为200～250 U/L占54.8%,BALP≤200 U/L占2.1%;男性中钙摄入不足者占48.4%,女性中占39.0%;各年龄组钙的摄入能满足机体需求的均不到10.0%;尤其是10～13岁年龄段儿童,明确缺钙者所占比例均>45.0%;不同性别、不同年龄间BALP均值差异无统计学意义,性别t=1.633,P=0.105;年龄F=0.323,P=0.924.经过遗传度分析,单卵双生(MZ)对内方差=191.54,对间方差=1462.22,相关系数=0.77;双卵双生(DZ)对内方差=491.03,对间方差=1475.57,相关系数=0.50;BALP活性的遗传度为0.54. 结论 青春前期的双生子普遍存在缺钙问题;BALP的活性遗传因素占54%,环境因素占46%.     

中国成年双生子饮茶行为分布特征

目的 描述中国双生子登记系统（CNTR）成年双生子饮茶行为的分布特征,探索饮茶行为在双生子人群中的分布规律,为探究遗传和环境因素对饮茶行为的影响提供线索。方法 样本选自2010-2018年在CNTR进行登记的双生子,纳入≥18岁且具有饮茶信息的双生子共25 264对进行分析,描述双生子中饮茶行为的人群、地区分布特征,以及不同卵型双生子饮茶行为一致率和对内饮茶量差异分布情况。结果 研究对象年龄（35.38±12.45）岁,每周饮茶者占比17.0%,饮茶量（3.36±2.44）杯/d。男性、50~59岁、南方、城镇、文化程度高、双生子中先出生的个体中每周饮茶者比例较高（P<0.05）,未婚者中比例较低（P<0.001）。双生子对内分析发现同卵饮茶行为一致率均大于异卵,饮茶遗传度为13.45%（11.38%~15.51%）,除女性亚组外,不同性别、年龄、地区间饮茶一致率差异有统计学意义（均P<0.05）;根据性别、年龄、地区分层后仅男性同卵一致率始终呈大于异卵趋势。同性别双生子对内饮茶量差异在男性中呈现同卵小于异卵的特征（P<0.05）,而女性中差异不明显。结论 本研究双生子人群饮茶行为的分布存在人群和地区差异,饮茶行为主要受环境因素影响,遗传因素影响较弱,且遗传效应大小在不同性别、年龄、地区间不尽相同,性别可修饰这一遗传作用。     

The epidemiology of anencephaly and spina bifida in Izmir, Turkey, in the light of recent aetiological theories

The data from this study suggest that, in western Turkey, potato consumption and water hardness do not play a significant role in the aetiology of anencephaly and spina bifida (ASB). Several of the predictions of the fetus-fetus interaction theory are not supported. Other predictions could not be tested because of lack of information on the dizygotic (DZ) twinning rate. Twin data from this study, together with previous material containing explicit information on zygosity, suggest that true concordance of a particular neural tube anomaly occurs only in monozygotic (MZ) twins. It also seems that even ASB concordance occurs in DZ twins only at a rate comparable with recurrence in siblings. This confirms the earlier refutation (Field and Kerr, 1974) of the supposition of Nance (1971) that MZ twin pairs are strikingly discordant for ASB compared with DZ pairs. However, the evidence seems to go further than Field's assertion that MZ and DZ pairs are affected about equally. Concordance in DZ twins is in comparison with sibling data, but MZ pairs show a significantly higher rate of concordance in both categories. Finally, the incidence of ASB in Izmir compared with the areas of ethnic origin of the Turks, and the high representation of families from Balkan areas where the incidence more closely resembles that of Izmir, suggest that the genetic factor is important in this area.     

Early-life environment influencing susceptibility to cytomegalovirus infection: evidence from the Leiden Longevity Study and the Longitudinal Study of Aging Danish Twins

Human cytomegalovirus (CMV) is a common herpesvirus establishing lifelong persisting infection, which has been implicated in immunosenescence and mortality in the elderly. Little is known about how and when susceptibility to CMV infection is determined. We measured CMV seroprevalence in two genetically informative cohorts. From the Leiden Longevity Study (LLS) we selected long-lived sib-pairs (n=844) and their middle-aged offspring and the offspring's partners (n=1452). From the Longitudinal Study of Aging Danish Twins (LSADT) 604 (302 pairs) same-sex monozygotic (MZ) and dizygotic (DZ) twins aged 73-94 years were included (n=302 pairs). Offspring of the long-lived LLS participants had significantly lower seroprevalence of CMV compared to their partners (offspring: 42% vs. partners: 51%, P=0·003). Of 372 offspring living with a CMV-positive partner, only 58% were infected. The corresponding number for partners was 71% (P<0·001). In the LSADT, MZ and DZ twins had high and similar CMV-positive concordance rates (MZ: 90% vs. DZ: 88%, P=0·51) suggesting that shared family environment accounts for the similarity within twin pairs. Our findings suggest that susceptibility to CMV infection--even under continuous within-partnership exposure--appears to be more strongly influenced by early-life environment than by genetic factors and adult environment.     

Male factor infertility: a twin study

There is a considerable body of literature on the causes of female infertility, but far less is known about male factor infertility. We conducted a classical twin study to estimate the genetic influence on 12-month male factor infertility. The study used the Vietnam Era Twin (VET) Registry, which includes male twin pairs born between 1939 and 1957, and who served in the US military between 1965 and 1975. In 1987, a health survey was mailed to all twins and obtained a 74% response rate. The current analyses comprised 1795 complete pairs in which both twins were married only once. Proband-wise concordance rates, tetrachoric correlations, and a bivariate probit model were used to calculate estimates of familial clustering and heritability for male factor infertility. The proband concordance rate for male factor infertility was 38% [95% CI 32.8, 42.4] in monozygotic (MZ) pairs and 33% [95% CI 28.0, 38.6] in dizygotic (DZ) pairs. The tetrachoric correlations for male infertility were 0.15 in MZ and 0.04 in DZ pairs. This pattern provides evidence of familial clustering, although genetic influence was not evident (P = 0.21). The current study identified that 12-month male factor infertility clustered within families. However, results suggest that factors unique to individual twins may play a more prominent role in male infertility than additive genetic effects or the common environment.     

中国成年双生子体质指数的分布特征

目的 描述中国双生子登记系统（CNTR）成年双生子BMI的分布特征,探索BMI在双生子人群中的特殊分布规律,为超重及肥胖高危因素分析和制定防制策略提供线索和基础资料。方法 选自CNTR中2010-2018年完成问卷调查的双生子对,纳入≥ 18岁具有完整双生子对登记信息,且身高、体重等关键变量无缺失或异常者进行分析,共计32 725对成年双生子。描述CNTR项目成年双生子BMI的人群、地区分布特征及双生子对内成员BMI差异的分布现况。结果 研究对象年龄（34.6±12.4）岁,同性别双生子对79.7%。研究对象平均BMI为22.5 kg/m²,超重率为23.7%,肥胖率为4.9%。男性、50~59岁组、北方地区、低文化程度者、在婚者的双生子超重率和肥胖率相对更高（P<0.001）。同卵和异卵间差异无统计学意义,但先出生的双生子超重和肥胖率略高于后出生者（P<0.05）。同性别双生子对内分析发现,对内BMI差异与年龄呈正相关（趋势性检验P<0.001）,异卵差异高于同卵,且卵型间差异随年龄增长发生变化。BMI一致率存在卵型差异（P<0.05）,同卵高于异卵。结论 本研究的双生子人群BMI的分布存在人群和地区差异;BMI为可遗传的性状,且遗传作用可能随年龄而变化。     

双生子艾森克人格与血液生化指标的相关性研究

[目的 ]了解双生子艾森克人格特点及遗传因素对艾森克人格的影响 ,探讨血液生化指标与艾森克人格的相关性。 [方法 ] 2 0 0 1年 12月对青岛市 89对 2 4岁以上的双生子 (同卵 5 5对 ,异卵 3 4对 )进行艾森克人格测试 ,检测 3 7项血液生化指标 ,并进行相关分析。 [结果 ]同卵双胞胎之间在N(情绪稳定性 )因子的相关系数高于异卵双胞胎 ,N因子的遗传度为 0 45。人格因素中只有N因子与几项生化指标有相关关系 (r <0 3 0 )。 [结论 ]艾森克人格因素中的N因子受遗传作用的倾向较大 ,血液生化指标水平并不决定人的个性心理特征。     

遗传与环境因素对女性青春期性征发育的影响

目的探讨遗传与环境因素对女性青春期性征发育的影响,为进一步深入研究女性青春期发育提供依据。方法以学校登记为基础,募集6~18岁女性双生子180对,其中单卵双生(MZ)132对,二卵双生(DZ)48对,按Tanner标准进行青春发育分期,询问有无月经初潮及月经初潮年龄。结果乳房开始发育的年龄为9~12岁,阴毛开始发育的年龄集中在9~13岁,月经初潮年龄多集中在11~13岁。月经初潮、性征发育一致率均为MZ>DZ,月经初潮的遗传指数为0.71,乳房和阴毛发育的遗传指数分别为0.34,0.45。月经初潮年龄的组内相关系数MZ>DZ(P<0.001),偶内均方MZ相似文献   

Intrapair comparisons of diet and food preference in adult twins

OBJECTIVES: An investigation was conducted on the influence of genetic and lifestyle factors related to the determination of eating behavior of human beings. The objective was to obtain information about lifestyle factors that may help health professionals intervene in terms of the prevention of diet-related diseases. METHODS: The subjects were 180 pairs of adult twins aged over thirty, comprising of 134 monozygotic (MZ) and 46 dizygotic (DZ) pairs. Every subject was given an interview concerning dietary habits, food preference, food intake, as a part of medical examination. The intake of food containing salt and fat, the intake of food meals, the frequency of daily meals, and the frequency of eating 18 sorts of food were assessed on an individual basis, with a questionnaire on nutrition. The expected and observed values of intrapair concordance rates were calculated, and compared within each zygosity, using the chi-square test. RESULTS: Significant differences between the expected and observed for intrapair concordance rates were shown with monozygotic twins, regarding every category of question. Comparing MZ pairs who had lived apart before their twenties with the other MZ pairs, the latter had a tendency to show significant differences between the expected and observed values of intrapair concordance rate, regarding every category of question. In each case, the observed values were higher than the expected values. CONCLUSIONS: The study implied that both genetic and lifestyle factors influence the determinants of eating behavior of human beings. This finding shows the importance of understanding individual characteristics of food preference and eating behavior for intervention regarding lifestyle factors for prevention of diet-related diseases.     

Concordance of ischemic heart disease in the NHLBI twin study after 14-18 years of follow-up

Morbidity and mortality were assessed in the NHLBI twin study at the end of 1987. Deaths were greater in DZ twins (58/520, 11.2%) than MZ twins (38/508, 7.5%). Ischemic heart disease concordances were 2.3 times higher in MZ pairs and 2.8 times higher in DZ pairs than expected based on the prevalence of ischemic heart disease in the cohort. Family history scores for heart disease, calculated 14-18 years earlier at entry to the study, were significantly higher in DZ pairs where one or both members later developed ischemic heart disease and in corcordant MZ pairs than in twin-pairs without any subsequent heart disease. Concordance rates were not significantly different between MZ and DZ pairs. The results agree with previous suggestions that selection at enlistment into the armed services over 40 years ago, as well as later volunteering for the NHLBI twin study, resulted in a decline in the number of concordant MZ pairs.