What is a cohort effect? Comparison of three statistical methods for modeling cohort effects in obesity prevalence in the United States, 1971-2006.
What is a cohort effect? Comparison of three statistical methods for modeling cohort effects in obesity prevalence in the United States, 1971-2006.
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DOI：
10.1016/j.socscimed.2009.12.018
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发表时间：
2010-04
影响因子：
5.4
通讯作者：
Li, Guohua
中科院分区：
文献类型：
--
作者：
Keyes, Katherine M.;Utz, Rebecca L.;Robinson, Whitney;Li, Guohua
分析师经常对队列效应使用不同的概念定义，因此使用不同的统计方法，从而导致不同的经验结果。社会学中经常使用的一个定义假设，队列具有被年龄和时期效应混淆的独特特征，而流行病学家通常认为，时期和年龄效应相互作用，产生队列效应。本研究旨在通过使用这两种概念方法估计年龄、时期和队列(APC)对1971年至2006年美国肥胖率的影响来说明这些差异。数据来自全国健康和营养检查调查的七个横断面波浪图。肥胖定义为成人体重指数≥30，20岁以下儿童≥95百分位数。采用经典的基于约束的方法(一阶效应估计和解释)、霍尔福德方法(一阶效应估计但二阶效应解释)和中位数波兰法(二阶效应估计和解释)估计APC效应。结果表明，所有方法都报告了显著的年龄和时期效应，在连续的调查中，早期肥胖率较低，而肥胖率有所增加。在基于约束的模型的基础上，较新出生的队列出现了正的队列效应；当队列效应被考虑为二阶估计时，没有出现显著的影响。对年龄-时期-队列效应的一阶估计经常受到批评，因为它们依赖于任意的限制，但对于社会学研究问题可能在概念上有意义。二阶估计在统计上是可估计的，并为流行病学研究问题产生概念上有意义的结果。年龄-时期-队列分析人员应明确说明正在考虑的队列效应的定义。我们的分析表明，20世纪后半叶美国肥胖率在所有出生队列中都有所上升，这是基于估计的年龄和时期效应而预期的方式。因此，队列效应的存在与否取决于概念定义，因此也取决于所使用的统计方法。
Analysts often use different conceptual definitions of a cohort effect, and therefore different statistical methods, which lead to differing empirical results. A definition often used in sociology assumes that cohorts have unique characteristics confounded by age and period effects, whereas epidemiologists often conceive that period and age effects interact to produce cohort effects. The present study aims to illustrate these differences by estimating age, period, and cohort (APC) effects on obesity prevalence in the U.S. from 1971–2006 using both conceptual approaches. Data were drawn from seven cross-sectional waves of the National Health and Nutrition Examination Survey. Obesity was defined as BMI≥30 for adults and ≥95th percentile for children under the age of 20. APC effects were estimated using the classic constraint-based method (first-order effects estimated and interpreted), the Holford method (first-order effects estimated but second-order effects interpreted), and median polish method (second-order effects are estimated and interpreted). Results indicated that all methods report significant age and period effects, with lower obesity prevalence in early life as well as increasing prevalence in successive surveys. Positive cohort effects for more recently born cohorts emerged based on the constraint-based model; when cohort effects were considered second-order estimates, no significant effects emerged. First-order estimates of age-period-cohort effects are often criticized because of their reliance on arbitrary constraints, but may be conceptually meaningful for sociological research questions. Second-order estimates are statistically estimable and produce conceptually meaningful results for epidemiological research questions. Age-period-cohort analysts should explicitly state the definition of a cohort effect under consideration. Our analyses suggest that the prevalence of obesity in the U.S. in the latter part of the 20th century rose across all birth cohorts, in the manner expected based on estimated age and period effects. As such, the absence or presence of cohort effects depends on the conceptual definition and therefore statistical method used.
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影响因子：
120.7
作者：
Flegal, KM;Carroll, MD;Johnson, CL
通讯作者：
Johnson, CL
影响因子：
7.1
作者：
Kivimaeki, Mika;Lawlor, Debbie A.;Raitakari, Olli T.
通讯作者：
Raitakari, Olli T.
影响因子：
9.1
作者：
MASON, KO;WINSBORO.HH
通讯作者：
WINSBORO.HH
影响因子：
16.2
作者：
Kwon, Jin-Won;Song, Yun-Mi;Cho, Sung-Il
通讯作者：
Cho, Sung-Il
影响因子：
7.7
作者：
McNally, RJQ;Alexander, FE;Cartwright, RA
通讯作者：
Cartwright, RA