Prior health care utilization as a determinant to enrollment in a twenty-year prospective study, the Millennium Cohort Study

Biomechanics Branch, Air Force Research Laboratory, Wright-Patterson Air Force Base, Building 824, Dayton, OH, USA.
European Journal of Epidemiology (Impact Factor: 5.34). 02/2008; 23(2):79-87. DOI: 10.1007/s10654-007-9216-0
Source: PubMed


Results obtained from self-reported health data may be biased if those being surveyed respond differently based on health status. This study was conducted to investigate if health, as measured by health care use preceding invitation, influenced response to invitation to a 21-year prospective study, the Millennium Cohort Study. Inpatient and outpatient diagnoses were identified among more than 68,000 people during a one-year period prior to invitation to enroll. Multivariable logistic regression defined how diagnoses were associated with response. Days spent hospitalized or in outpatient care were also compared between responders and nonresponders. Adjusted odds of response to the questionnaire were similar over a diverse range of inpatient and outpatient diagnostic categories during the year prior to enrollment. The number of days hospitalized or accessing outpatient care was very similar between responders and nonresponders. Study findings demonstrate that, although there are some small differences between responders and nonresponders, prior health care use did not affect response to the Millennium Cohort Study, and it is unlikely that future study findings will be biased by differential response due to health status prior to enrollment invitation.

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Available from: Timothy S Wells, Aug 13, 2014
    • "Additionally, the data used from the Millennium Cohort Study Questionnaire were self-reported, which may be subject to recall and reporting biases. Investigations of potential biases in the Millennium Cohort Study however, have found the participants report reliable health and military data and were not influenced to participate by poor health prior to enrollment (Smith, Smith, Jacobson, Corbeil, & Ryan, 2007; Wells et al., 2008). In addition, we conducted a sensitivity analysis consisting of all eligible participants (n = 19,247). "
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    ABSTRACT: Sexual trauma is prevalent among military women, but data on potential effects are needed. The association of sexual trauma with health and occupational outcomes was investigated using longitudinal data from the Millennium Cohort Study. Of 13,001 U.S. service women, 1,364 (10.5%) reported recent sexual harassment and 374 (2.9%) recent sexual assault. Women reporting recent sexual harassment or assault were more likely to report poorer mental health: OR = 1.96, 95% CI [1.71, 2.25], and OR = 3.45, 95% CI [2.67, 4.44], respectively. They reported poorer physical health: OR = 1.39, 95% CI [1.20, 1.62], and OR = 1.39, 95% CI [1.04, 1.85], respectively. They reported difficulties in work/activities due to emotional health: OR = 1.80, 95% CI [1.59, 2.04], and OR = 2.70, 95% CI [2.12, 3.44], respectively. They also reported difficulties with physical health: OR = 1.55, 95% CI [1.37, 1.75], and OR = 1.52 95% CI [1.20, 1.91], respectively, after adjustment for demographic, military, health, and prior sexual trauma characteristics. Recent sexual harassment was associated with demotion, OR = 1.47, 95% CI [1.12, 1.93]. Findings demonstrated that sexual trauma represents a potential threat to military operational readiness and draws attention to the importance of prevention strategies and services to reduce the burden of sexual trauma on military victims. Copyright © 2015 Wiley Periodicals, Inc., A Wiley Company.
    No preview · Article · Jul 2015 · Journal of Traumatic Stress
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    • "Additionally, prior health conditions may affect the probability of enrollment into an epidemiologic study, but most studies do not have these data on non-enrolled invitees. One study examining healthcare use in relation to enrollment of the first panel of the Millennium Cohort Study found some differences between responders and non-responders, but most differences were small in magnitude and it is unlikely that differential response due to health status substantially affected subsequent enrollment in Panel 1 [24]. Some studies of nonresponse have shown that individuals who receive more healthcare are more likely to respond to longitudinal studies [6,10,25-27]. "
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    ABSTRACT: Longitudinal cohort studies are highly valued in epidemiologic research for their ability to establish exposure-disease associations through known temporal sequences. A major challenge in cohort studies is recruiting individuals representative of the targeted sample population to ensure the generalizability of the study's findings. We evaluated nearly 350,000 invited subjects (from 2004-2008) of the Millennium Cohort Study, a prospective cohort study of the health of US military personnel, for factors prior to invitation associated with study enrollment. Multivariable logistic regression was utilized, adjusting for demographic and other confounders, to determine the associations between both deployment experience and prior healthcare utilization with enrollment into the study. Study enrollment was significantly greater among those who deployed prior to and/or during the enrollment cycles or had at least one outpatient visit in the 12 months prior to invitation. Mental disorders and hospitalization for more than two days within the past year were associated with reduced odds of enrollment. These findings suggest differential enrollment by deployment experience and health status, and may help guide recruitment efforts in future studies.
    Full-text · Article · Jul 2013 · BMC Medical Research Methodology
    • "This is the first study to analyze the association between deployment in support of the operations in Iraq and Afghanistan and sexual stressors in a large, population-based cohort of military women, including those who serve in the Reserves and National Guard. Numerous investigations for potential biases have found the Millennium Cohort to be representative of military personnel and suggest data reporting is reliable with minimal non-response bias (Chretien, Chu, Smith, Smith, & Ryan, 2007; LeardMann, Smith, Smith, Wells, & Ryan, 2007; Riddle et al., 2007; Ryan et al., 2007; Smith, Leard, Smith, Reed, & Ryan, 2007; Smith, Wingard, et al., 2007; Smith, Jacobson, Smith, Hooper, & Ryan, 2007; Smith, Zamorski, et al., 2007; Wells et al., 2008). Recall errors may also have been reduced, since outcome information was collected within a relatively short period (3 years) of the event(s). "
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    ABSTRACT: Background Previous studies have examined the prevalence, risk factors, and health correlates of sexual stressors in the military, but have been limited to specific subpopulations. Furthermore, little is known about sexual stressors' occurrence and their correlates in relation to female troops deployed to the current operations in Iraq and Afghanistan.Methods Using longitudinal data from Millennium Cohort participants, the associations of recent deployment as well as other individual and environmental factors with sexual harassment and sexual assault were assessed among U.S. female military personnel. Multivariable analyses were used to investigate the associations.FindingsOf 13,262 eligible participants, 1,362 (10.3%) reported at least one sexual stressor at follow-up. Women who deployed and reported combat experiences were significantly more likely to report sexual harassment (odds ratio [OR], 2.20; 95% confidence interval [CI], 1.84–2.64) or both sexual harassment and sexual assault (OR, 2.47; 95% CI, 1.61–3.78) compared with nondeployers. In addition, significant risk factors for sexual stressors included younger age, recent separation or divorce, service in the Marine Corps, positive screen for a baseline mental health condition, moderate/severe life stress, and prior sexual stressor experiences.Conclusions Although deployment itself was not associated with sexual stressors, women who both deployed and reported combat were at a significantly increased odds for sexual stressors than other female service members who did not deploy. Understanding the factors associated with sexual stressors can inform future policy and prevention efforts to eliminate sexual stressors.
    No preview · Article · Jul 2013 · Women s Health Issues
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