The Impact of Attrition in an 11-Year Prospective Longitudinal Study of Younger Women

doi:10.1016/j.annepidem.2010.01.002

Annals of Epidemiology

Volume 20, Issue 4, April 2010, Pages 318-321

https://doi.org/10.1016/j.annepidem.2010.01.002 Get rights and content

Purpose

To investigate the impact of attrition on prevalence and associations between variables across four waves of a longitudinal study.

Methods

Prevalence of socio-demographic and health characteristics were estimated for respondents to one, two, three or all four waves of the Australian Longitudinal Study of Women's Health cohort born between 1973 and 1978. Associations with self-rated General Health (GH) and Mental Health (MH) were compared using fixed effects in separate mixed models for respondents to at least one wave, at least two waves, at least three waves, or four waves of the longitudinal study.

Results

14,247 women aged 18-23 years responded to Wave 1 in 1996. Respondents to all waves were more educated, and less likely to be stressed about money, to be smokers and to have children than respondents to some waves. Across all models, better GH was consistently associated with more education, no monetary stress, being married, having children, fewer visits to the doctor and not smoking. Similar results were obtained for MH.

Conclusions

Although the potential for bias due to attrition must be considered, the current paper contributes to the growing body of evidence that suggests such biases are insufficient to preclude meaningful longitudinal analyses.

Introduction

Attrition or loss of study participants may bias the results of longitudinal studies (1). For example, findings indicate that smokers are less likely to respond and that healthier people may be more likely to respond to subsequent surveys 2, 3, 4. However, whether the associations between smoking and health are affected by attrition is not known. In this study, we investigate whether (i) the characteristics of respondents to one, two, three or all waves are different and (ii) the relationships between health and other variables differ for those who respond to some or all waves of a longitudinal study.

Section snippets

Methods

Data come from the first four waves of the Australian Longitudinal Study on Women's Health cohort born between 1973 and 1978 (the 1973–1978 cohort) (5). Surveys were mailed in 1996, 2000, 2003, and 2006.

Results

Almost half the women were consistent respondents, and more than 80% responded to at least two waves (Table 1). Nonresponse was permanent (6%), because of discontinued participation or death, or temporary, because of lack of contact with the participant (28%) or other nonresponse at the wave (8%). At wave 1, consistent respondents had more education, were less likely to have children, be stressed about money, and to be smokers than intermittent respondents (Table 1). Consistent respondents had

Discussion

Consistent respondents comprised one half of the initial sample. Nonresponse was related to baseline characteristics (eg, smoking, poorer health). Despite these differences, the relationships between self-rated health and education, stress about money, smoking, and general practitioner visits were similar, indicating there was no serious bias in estimates of associations caused by attrition. Standard errors were larger in consistent respondent models than those including intermittent

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Endometriosis has been linked to higher rates of a variety of symptoms; however, the findings from longitudinal studies are scarce and inconsistent.
This study aimed to examine the association between endometriosis and common symptoms in a prospective cohort study.
This study included 7606 women born from 1973 to 1978 using data from the Australian Longitudinal Study on Women’s Health that were collected every 3 years from 2009 to 2018. We identified women with endometriosis based on self-reported incidence from each survey and linked administrative health data. At each survey, women also completed a checklist on the presence of 24 symptoms. Generalized estimating equations for multinomial responses were used for analyses.
Women with endometriosis had significantly more menstrual symptoms than those without endometriosis with an adjusted odds ratio (95% confidence interval) of 3.61 (3.11–4.19) for severe period pain, 2.40 (2.10–2.74) for heavy menstrual bleeding, 1.76 (1.52–2.03) for irregular bleeding, and 1.52 (1.32–1.76) for premenstrual tension. They also had higher odds of mental health problems with adjusted odds ratios of 1.67 (1.39–2.01) for depression and 1.59 (1.24–2.03) for anxiety and higher odds of allergies and nonspecific symptoms with adjusted odds of 1.62 (1.40–1.89) for allergies or hay fever or sinusitis, 1.79 (1.56–2.05) for severe tiredness, 1.56 (1.35–1.81) for sleep difficulty, and 1.77 (1.37–2.18) for palpitations. There was also a strong association with other forms of pain with an adjusted odds ratio of 1.76 (1.53–2.04) for backpain, 1.50 (1.29–1.74) for headaches or migraines, and 1.65 (1.41–1.93) for stiff or painful joints. Women with endometriosis also had increased odds of developing bowel and urinary symptoms with an adjusted odds ratio (95% confidence interval) of 1.67 (1.35–2.08) for constipation, 1.46 (1.12–1.90) for hemorrhoids or piles, 1.25 (1.03–1.52) for indigestion or heartburn, 2.80 (1.71–4.58) for urine burn or stings, and 1.37 (1.03–1.82) for vaginal discharge or irritation. The association between each symptom and endometriosis was similar whether endometriosis was surgically confirmed or clinically suspected. No association was found between endometriosis and the risk for skin problems, leaking urine, or breathing difficulty.
This study suggests that women with endometriosis are more likely to report not only menstrual symptoms but are also at an increased risk for mental health problems, other pain symptoms, bowel and urinary symptoms, and nonspecific symptoms, such as severe tiredness and difficulty sleeping.
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A standard deviation (SD) (0.12 units) increase in NDVI_500m was significantly associated with lower odds of anxiety symptoms (OR: 0.96, 95% CI: 0.93–0.99) in the adjusted model. An SD (5.2%) increase in annual fNPV_500m was consistent with the direction expected for that exposure, but not significant in the adjusted model (OR: 1.03, 95% CI: 0.99–1.07). NDVI_500m was modestly attenuated when air pollutants were adjusted for, while fNPV_500m only became significant when PM_2.5 was adjusted for. Between-survey contrasts had no clear effect for NDVI_500m. Moving to a higher fNPV_500m area, compared with a similar fNPV_500m area, was consistently associated with anxiety symptoms (OR: 1.15, 95% CI: 1.02–1.31). NDVI_500m was generally associated with lower odds of anxiety symptoms, while fNPV_500m was generally associated with higher odds of anxiety, depending on the covariates considered.
Impact of endometriosis on women's health-related quality of life: A national prospective cohort study
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To examine the association between endometriosis and women's health-related quality of life (HRQoL).
This study included 3728 women born in 1973–78 using data from the Australian Longitudinal Study on Women's Health. Women with endometriosis were identified using self-reported longitudinal surveys linked to administrative health records. A mixed effect model with only random intercept and generalised estimating equations with binary logistic regressions were used to examine the association between endometriosis and health-related quality of life over eight time points. Each HRQoL scale was analysed in terms of binary outcomes by comparing women who had a lower HRQoL (scoring below the 25th percentile) with those who had a higher HRQoL (scoring above the 25th percentile).
Women's HRQoL was assessed using the 36-item Short Form Survey every 3 years from 1996 to 2018.
Endometriosis was associated with significantly worse reports of HRQoL over time. In the comparison against women without endometriosis, the following adjusted odds ratios (95 % confidence intervals) were calculated for women with endometriosis having worse scores on the eight domains of the Short Form Survey: physical functioning 1.33 (1.19, 1.50), role physical 1.57 (1.41, 1.74), bodily pain 1.65 (1.48, 1.82), general health 1.61 (1.42, 1.81), vitality 1.38 (1.23, 1.55), social functioning 1.38 (1.25, 1.53), role emotion 1.19 (1.06, 1.33), mental health 1.32 (1.18, 1.48). Women with endometriosis also had significantly lower physical health 1.68 (1.51, 1.88) and mental health components scores 1.28 (1.14, 1.44).
Endometriosis is associated with worse physical, mental, and social functioning and well-being. Bodily pain was the most affected HRQoL domain.
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Citation Excerpt :
Participant characteristics were mostly comparable with national census data across time (e.g. at Survey 1 in 1996 (Brown et al., 1996), and Survey 6 in 2011 (Dobson et al., 2015), although Australian-born, married and tertiary educated participants were slightly overrepresented (Brown et al., 1996; Dobson et al., 2015). The response rates among women contacted at each of the follow-up surveys (Survey 2–7) were stable above 80% (Powers and Loxton, 2010). The response rate to each survey is comparable with other cohort studies (Mostafa, 2014) (Bethel et al., 2005).
In Australia, 8.6% of all births are premature, and this figure has relativelyincreased by 10% in the past decade. A range of biological, psychological, and socialfactors have previously been identified as predictors of preterm birth using cross sectionaldata; however, this lacks ascertainment of a cause-and-effect relationship.This study harnessed the power of longitudinal cohort data by investigating pretermbirth among women prospectively followed for 19 years using a comprehensiveframework that examines biological, psychological, and social factors concurrently.
Data from 5,292 women (11,256 newborns) who reported singleton birthsbetween 1996 and 2015 in the Australian Longitudinal Study on Women’s Health wereincluded.
The prevalence of preterm birth was 8.5% for first-births and 5.9% for allbirths.The recurrent preterm birth rate was 9.5% . Risk factors for first preterm birthswere chronic hypertension (OR 2.34; 95% CI: 1.67-3.27), gestational hypertension (OR2.87; 95% CI: 2.22-3.72), gestational diabetes (OR 1.66; 95% CI: 1.14-2.41),menarche before 12 years (OR 1.36; 95% CI: 1.02-1.82) and history of miscarriage(OR 1.35; 95% CI: 1.01-1.79). Risk factors for all preterm births were a history ofpreterm birth (OR 2.33; 95% CI: 1.46-3.70), menarche before 12 years (OR 1.33; 95%CI: 1.00-1.77), not being partnered (OR 1.31; 95% CI: 1.02-1.69), chronic hypertension(OR 2.02; 95% CI: 1.45-2.82), gestational hypertension (OR 3.22; 95% CI: 2.43-4.25),gestational diabetes (OR 1.67; 95% CI: 1.16-2.41), and asthma (OR 1.40; 95% CI:1.14-1.72). Premature birth was less likely for second or later births (OR 0.44; 95% CI:0.36-0.55) compared to first births. Premature birth was also less likely for women whocompleted a university degree compared to women with a high school certificate (OR0.73; 95% CI: 0.57-0.94).
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Citation Excerpt :
Further, the matched comparison group of women without endometriosis in this study were more likely to have attended university than the non–matched women. Women who were randomly selected for matching were more consistent responders to the ALSWH surveys, and consistent responders are more likely to be university educated [29]. Consequently, the differences in labor force participation for women with surgically confirmed endometriosis, and women without endometriosis may be underestimated.
Endometriosis is a chronic inflammatory disease affecting the reproductive, gastrointestinal, and urinary systems. We examined changes in labor force participation amongst women with endometriosis following diagnosis.
We analyzed data from 4494 women born in 1973–78 from the Australian Longitudinal Study on Women's Health. We used multinomial logistic regression models with generalized estimating equations to examine changes in labor force participation amongst 468 women with surgically confirmed endometriosis, and 375 women with clinically suspected endometriosis, relative to a comparison group of 4151 women without endometriosis.
At diagnosis, women with surgically confirmed endometriosis were somewhat more likely to be working part-time (OR 1.26, 95% CI 0.94–1.68) or unemployed (OR 1.46, 95% CI 0.96–2.23) than before diagnosis. After diagnosis, women with surgically confirmed endometriosis remained somewhat more likely to be working part-time (OR 1.26, 95% CI 0.88–1.80) but were significantly more likely to be unemployed (OR 1.85, 95% CI 1.16–2.96) than before diagnosis. Labor force participation for women with clinically suspected endometriosis did not differ from women without endometriosis at diagnosis and did not change over time.
Women with surgically confirmed endometriosis transitioned out the labor force following diagnosis. Supportive workplace practices may help women remain in the labor force.

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Brief CommunicationThe Impact of Attrition in an 11-Year Prospective Longitudinal Study of Younger Women

Purpose

Methods

Results

Conclusions

Introduction

Section snippets

Methods

Results

Discussion

J Clin Epidemiol

J Clin Epidemiol

Controlled Clinical Trials

J Clin Epidemiol

Survey nonresponse bias among young adults: The role of alcohol, tobacco, and drugs

Substance Use & Misuse

Brief Communication
The Impact of Attrition in an 11-Year Prospective Longitudinal Study of Younger Women