Rebecca L. Utz

What is a cohort effect? Comparison of three statistical methods for modeling cohort effects in obesity prevalence in the United States, 1971–2006

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 to 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 >or=30 for adults and >or=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.

Religion and Emotional Compensation: Results from a Prospective Study of Widowhood

Based on recent applications of attachment theory to religion, the authors predicted that the loss of a spouse would cause widowed individuals to increase the importance of their religious/spiritual beliefs. This hypothesis was examined using the Changing Lives of Older Couples sample from which preloss measures of religiosity were available for widowed individuals and matched controls. A total of 103 widowed individuals provided follow-up data, including reports of religious beliefs and grief, at 6 months, 24 months, and 48 months after the loss. Results indicated that widowed individuals were more likely than controls to increase their religious/spiritual beliefs. This increase was associated with decreased grief but did not influence other indicators of adjustment such as depression. Finally, insecure individuals were most likely to benefit from increasing the importance of their beliefs. Results are discussed in terms of the potential value of applying psychological theory to the study of religion.

The Daily Consequences of Widowhood The Role of Gender and Intergenerational Transfers on Subsequent Housework Performance

This study examines (a) whether widowhood affects the performance of daily household activities, (b) the extent to which dependence on children mediates the effect of widowhood on subsequent housework performance, and (c) the extent to which these patterns vary by gender. Using the Changing Lives of Older Couples study, a prospective survey of married persons age 65 and older, we find that late-life widowhood is associated with an increase in men’s housework, yet does not produce a change in women’s subsequent housework performance. Dependency on children mediates the effect of widowhood on housework, suggesting that adult children assist their grieving parents with errands and other household chores. Findingsimplythat the daily consequencesof late-life widowhoodare dependenton the individual, dyadic, and intergenerational characteristics of the older adult.

Stress-related growth among the recently bereaved

Although stress-related growth (SRG), or a personal transformation beyond adaptation, can be an outcome for some individuals after a traumatic life experience like spouse or partner loss, it is often assumed that some time needs to pass before this happens. This study reports on early experiences of SRG relatively soon after the loss of a spouse or partner in mid and later life. Self-administered questionnaires were completed by 292 recently bereaved (2–6 months) partners, aged 50+, as part of the Living After Loss study conducted in Salt Lake City and San Francisco. Substantial variability in SRG was observed where 21% scored ≥1 SD above and approximately 18% scored ≥1 SD below the sample mean of 17.2 (SD = 7.0). Regression analyses revealed that SRG was more likely for those who had expected their partners’ deaths, who were more religious and who engaged in loss- and restoration-oriented coping processes, and was independent of grief levels. Findings suggest that some individuals drew upon their religious beliefs as a way to find meaning and make sense of what happened as they rebuilt their ‘assumptive world’. Also, those who anticipated their partners death could have had more opportunity to cognitively process the loss, address the challenges of widowed life and learn new skills and discover previously unrecognized strengths.

Birth cohort effects on abdominal obesity in the United States: the Silent Generation, Baby Boomers and Generation X

BACKGROUND:Abdominal obesity predicts a wide range of adverse health outcomes. Over the past several decades, prevalence of abdominal obesity has increased markedly in industrialized countries like the United States No previous analyses, however, have evaluated whether there are birth cohort effects for abdominal obesity. Estimating cohort effects is necessary to forecast future health trends and understand the past population-level trends.METHODS:This analysis evaluated whether there were birth cohort effects for abdominal obesity for the Silent Generation (born 1925–1945), children of the Great Depression; Baby Boomers (born 1946–1964); or Generation X (born 1965–1980). Cohort effects for prevalence of abdominal obesity were estimated using the median polish method with data collected from the National Health and Nutrition Examination Survey (NHANES) between 1988 and 2008. Respondents were aged 20–74 years.RESULTS:After taking into account age effects and ubiquitous secular changes, the Silent Generation and Generation X had higher cohort-specific prevalence of abdominal obesity than the Baby Boomers. Effects were more pronounced in women than men.CONCLUSIONS:This work presents a novel finding: evidence that the birth cohorts of the post-World War II Baby Boom appeared to have uniquely low cohort effects on abdominal obesity. The growing prosperity of the post-World War II US may have exposed the baby-boom generation to lower levels of psychosocial and socioeconomic stress than the previous or subsequent generations. By identifying factors associated with the Baby Boomers’ low cohort-specific sensitivity to the obesogenic environment, the obesity prevention community can identify early-life factors that can protect future generations from excess weight gain.

A Multivariate Analysis of Federally Mandated School Wellness Policies on Adolescent Obesity

PURPOSE To evaluate the effects of school wellness policies mandated by the 2004 Child Nutrition and WIC Reauthorization Act on the prevalence of overweight and obesity among adolescents. METHODS Multivariate logistic regressions, adjusted for clustering within school districts, were used to estimate the effects of district-level wellness policies on the odds of overweight and obesity among adolescents. The analyses were performed on a population-based sample obtained from the Utah Population Database, a compilation of vital characteristic, administrative, and genealogical records on all residents in Utah. Models controlled for individual, maternal, and familial characteristics, as well as characteristics of school district of residence. Self-reported body mass index was taken from drivers license data. RESULTS Each additional component included in a districts wellness policy was associated with as much as: 3.2% lower odds in the prevalence of adolescent overweight (OR = .968; 95% CI = .941-.997), 2.5% lower odds of obesity (OR = .975; CI = .952-.997), and 3.4% lower odds of severe obesity (OR = .966; CI = .938-.995). Wellness policy components related to diet were significantly associated with lower body mass indexes across all three thresholds, whereas those related to physical activity had significant associations for lower odds of severe obesity only. CONCLUSION Results suggest that school wellness policies can significantly reduce the risk of adolescent obesity. Further research should address specific policy components that are most effective in various populations, as well as the level of commitment that is required at both the school- and district-levels for sustained effect.

Experiences and Early Coping of Bereaved Spouses/Partners in an Intervention Based on the Dual Process Model (DPM)

This study was designed to test the effectiveness of the Dual Process Model (DPM) of coping with bereavement. The sample consisted of 298 recently widowed women (61%) and men age 50+ who participated in 14 weekly intervention sessions and also completed before (O1) and after (O2) self-administered questionnaires. While the study also includes two additional follow-up assessments (O3 and O4) that cover up to 14–16 months bereaved, this article examines only O1 and O2 assessments. Based on random assignment, 128 persons attended traditional grief groups that focused on loss-orientation (LO) in the model and 170 persons participated in groups receiving both the LO and restoration-orientation (RO) coping (learning daily life skills). As expected, participants in DPM groups showed slightly higher use of RO coping initially, but compared with LO group participants they improved at similar levels and reported similar high degrees of satisfaction with their participation (i.e., having their needs met and 98–100% indicating they were glad they participated. Even though DPM participants had six fewer LO sessions, they showed similar levels of LO improvement. Qualitative data indicate that the RO component of the DPM might be more effective if it is tailored and delivered individually.

Assisted Living: The Philosophical Challenges of Everyday Practice

Assisted living represents a philosophy to provide residential long-term care in a home-like environment that maximizes autonomy and independence for its residents. This article explores the question of whether providers achieve this philosophy in their everyday practice. Results are based on mail surveys and semistructured interviews with assisted living providers. Findings suggest that providers are united under a common philosophy yet struggle with how to provide care that balances their philosophical goals with more traditional business considerations. Management training—specifically, whether one is licensed as a nursing home administrator—is associated with poorer philosophical performance. Results also indicate that services and amenities are directly proportional to average monthly costs, but adoption of the assisted living philosophy, which presumably increases the quality of life for residents, has a far smaller impact on consumer costs. Results are discussed in terms of both practice and policy issues related to the industry.

Birth cohort effects among US-born adults born in the 1980s: foreshadowing future trends in US obesity prevalence

Background:Obesity prevalence stabilized in the US in the first decade of the 2000s. However, obesity prevalence may resume increasing if younger generations are more sensitive to the obesogenic environment than older generations.Methods:We estimated cohort effects for obesity prevalence among young adults born in the 1980s. Using data collected from the National Health and Nutrition Examination Survey between 1971 and 2008, we calculated obesity for respondents aged between 2 and 74 years. We used the median polish approach to estimate smoothed age and period trends; residual non-linear deviations from age and period trends were regressed on cohort indicator variables to estimate birth cohort effects.Results:After taking into account age effects and ubiquitous secular changes, cohorts born in the 1980s had increased propensity to obesity versus those born in the late 1960s. The cohort effects were 1.18 (95% CI: 1.01, 1.07) and 1.21 (95% CI: 1.02, 1.09) for the 1979–1983 and 1984–1988 birth cohorts, respectively. The effects were especially pronounced in Black males and females but appeared absent in White males.Conclusions:Our results indicate a generational divergence of obesity prevalence. Even if age-specific obesity prevalence stabilizes in those born before the 1980s, age-specific prevalence may continue to rise in the 1980s cohorts, culminating in record-high obesity prevalence as this generation enters its ages of peak obesity prevalence.

Humor, laughter, and happiness in the daily lives of recently bereaved spouses.

The positive psychology movement has created more interest in examining the potential value of experiencing positive emotions (e.g., humor, laughter, and happiness) during the course of bereavement. This study of 292 recently widowed (5–24 weeks) men (39%) and women (61%) age 50 and over examined both the perceived importance of and actual experience of having positive emotions in their daily lives and how they might impact bereavement adjustments. We found that most of the bereaved spouses rated humor and happiness as being very important in their daily lives and that they were also experiencing these emotions at higher levels than expected. Experiencing humor, laughter, and happiness was strongly associated with favorable bereavement adjustments (lower grief and depression) regardless of the extent to which the bereaved person valued having these positive emotions.