National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark.
Scand J Public Health. 2010 Aug;38(6):648-56. doi: 10.1177/1403494810374222. Epub 2010 Jun 7.
The aim of this paper is to describe the design and methods used in the Danish Youth Cohort and to give a description of the study participants with special attention to a comparison between participants and non-participants regarding sociodemographic characteristics.
A total of 1,945 schools were invited, out of which 506 participated. The participating 7th grades comprised a total of 12,498 responding adolescents. The response rate for the Danish Youth Cohort established in 2005 was 63%. The sample of 12,498 adolescents represents 18.2% of all pupils (n = 68,764) in the 7th grade (mean age: 13.4 years) in Danish schools in 2005. The cohort was followed up in spring 2006 and spring 2007, where the adolescents were in the 8th (mean age: 14.4 years) and 9th (mean age: 15.3 years) grades, respectively.
We found that compared with non-participants the participants were significantly more likely to be girls, to be of Danish ethnicity, and to live in one-family houses. Furthermore, participants more often came from families with two or three children, were more likely to have parents with a high occupational status, parents who were married and parents with a higher total income. Loss to follow-up was only associated with adolescents' higher probability of drinking and use of tobacco, and none of the other factors were associated with attrition.
The participants in the Danish Youth Cohort represent a great variety of different groups of socio-demographic factors, although they differ from non-participants as regards a range of socio-demographic factors. This should be taken into account in future analyses.
本文旨在描述丹麦青少年队列的设计和方法，并特别关注参与者与非参与者在社会人口特征方面的差异。
共邀请了 1945 所学校，其中 506 所学校参与。参与的 7 年级共有 12498 名回应的青少年。2005 年建立的丹麦青少年队列的应答率为 63%。12498 名青少年的样本代表了 2005 年丹麦学校 7 年级（平均年龄 13.4 岁）所有学生（n=68764）的 18.2%。该队列在 2006 年春季和 2007 年春季进行了随访，此时青少年分别处于 8 年级（平均年龄 14.4 岁）和 9 年级（平均年龄 15.3 岁）。
我们发现，与非参与者相比，参与者更有可能是女孩，具有丹麦血统，并且居住在独户住宅中。此外，参与者更可能来自有两个或三个孩子的家庭，其父母更有可能具有较高的职业地位、已婚和总收入较高。失访仅与青少年饮酒和吸烟的可能性增加有关，而其他因素均与失访无关。
丹麦青少年队列的参与者代表了各种不同的社会人口因素群体，尽管他们在一系列社会人口因素方面与非参与者有所不同。在未来的分析中应考虑到这一点。
