Ohlsson Claes, Bygdell Maria, Celind Jimmy, Sondén Arvid, Tidblad Anders, Sävendahl Lars, Kindblom Jenny M
Centre for Bone and Arthritis Research, Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, the Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
Bioinformatics Core Facility, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.
JAMA Pediatr. 2019 Sep 1;173(9):860-865. doi: 10.1001/jamapediatrics.2019.2315.
A secular trend for earlier menarcheal age has been established in girls but there are few studies of pubertal timing for boys.
To determine if there is a secular trend for earlier pubertal timing among boys.
DESIGN, SETTING, AND PARTICIPANTS: For this population-based retrospective cohort study conducted in Gothenburg, Sweden, we collected heights and weights from school health records for boys born consecutively from January 1 and onwards in 1947 and every 5 years from 1951 to 1996 (n = 375 for each birth cohort from 1947-1991, n = 340 for the birth cohort in 1996, and n = 4090 for the total cohort). We estimated age at the peak height velocity (PHV), the maximum growth velocity during puberty, and childhood body mass index (BMI) at age 8 years for all study participants. The data were analyzed during 2018 and 2019. Boys were eligible if they had a complete personal identity number and data to calculate their age at PHV and childhood BMI. Approximately 2.4% of the original study population was excluded because they lacked a personal identity number, and in the remaining study population, 4090 (69%) had sufficient data to calculate childhood BMI and age at PHV.
The exposure was birth year and a potential confounding factor was childhood BMI.
The outcome was age at PHV.
Of the 4090 participants, most were white and the mean (SD) age at PHV was 13.9 (1.1) years. A linear regression model revealed a significant association between year of birth and age at PHV. Age at PHV was 1.5 months earlier for every decade increase in birth year (95% CI, -1.72 to -1.19; P < .001). After adjusting for childhood BMI, age at PHV was 1.2 months earlier per decade increase in birth year (95% CI, -1.41 to -0.89). All analyses were repeated in the subgroup of boys born in Sweden and with parents born in Sweden with similar results, indicating that the secular trend was not explained by demographic changes in the population between 1947 and 1996.
We provide evidence of a secular trend for earlier pubertal timing in boys that is partially explained by an increased childhood BMI, but other factors that are unknown contribute.
女孩月经初潮年龄提前的长期趋势已得到证实，但关于男孩青春期发育时间的研究较少。
确定男孩青春期发育时间是否存在提前的长期趋势。
设计、地点和参与者：在瑞典哥德堡进行的这项基于人群的回顾性队列研究中，我们从学校健康记录中收集了1947年1月1日及以后连续出生的男孩以及1951年至1996年每5年出生队列的身高和体重数据（1947 - 1991年每个出生队列n = 375，1996年出生队列n = 340，总队列n = 4090）。我们估算了所有研究参与者的身高增长峰值速度（PHV）时的年龄（青春期最大生长速度）以及8岁时的儿童体重指数（BMI）。数据于2018年和2019年进行分析。具备完整个人身份号码且有数据可计算其PHV时年龄和儿童BMI的男孩符合入选条件。约2.4%的原始研究人群因缺少个人身份号码被排除，在其余研究人群中，4090人（69%）有足够数据计算儿童BMI和PHV时年龄。
暴露因素为出生年份，潜在混杂因素为儿童BMI。
结局为PHV时的年龄。
在4090名参与者中，大多数为白人，PHV时的平均（标准差）年龄为13.9（1.1）岁。线性回归模型显示出生年份与PHV时的年龄之间存在显著关联。出生年份每增加一个十年，PHV时的年龄提前1.5个月（95%CI， - 1.72至 - 1.19；P <.001）。在调整儿童BMI后，出生年份每增加一个十年，PHV时的年龄提前1.2个月（95%CI， - 1.41至 - 0.89）。在瑞典出生且父母也在瑞典出生的男孩亚组中重复了所有分析，结果相似，表明1947年至1996年期间人群的人口结构变化并不能解释这种长期趋势。
我们提供了证据表明男孩青春期发育时间存在提前的长期趋势，部分原因是儿童BMI增加，但其他未知因素也有影响。
