The Healthy Participant Effect: insights and results from a population-based case-control study on breast cancer.

Agreement to participate in case-control studies has become low. Healthy participant bias resulting from differential response proportions in cases and controls can distort results; however, the magnitude of bias is difficult to assess. We investigated the effect in a large population-based case-control study on breast cancer, with a participation rate of 43.4% and 64.1% for controls and cases. We performed a mortality follow-up in 2020 for 3,813 cases and 7,335 controls recruited between 2002-2005. Standardized mortality ratios (SMR) for overall mortality and selected causes of death were estimated. The mean age at recruitment was 63.1 years. The overall mortality for controls was 0.66 times lower (95%CI 0.62-0.69) than for the reference population. For causes of death other than breast cancer, SMRs were similar in cases and controls (0.70 and 0.64). Higher education was associated with lower SMRs in both cases and controls. Options for adjusting the healthy participant bias are limited if the true risk factor distribution in the underlying population is unknown. However, a relevant bias in this particular case-control study is considered unlikely since a similar healthy participant effect was observed for both controls and cases.

Does breast cancer modify the long-term relationship between lifestyle behaviors and mortality? A prospective analysis of breast cancer survivors and population-based controls.

BACKGROUND: Modifiable lifestyle factors are known to impact survival. It is less clear whether this differs between postmenopausal women ever diagnosed with breast cancer and unaffected women. METHODS: Women diagnosed with breast cancer and unaffected women of comparable age were recruited from 2002 to 2005 and followed up until 2020. Using baseline information, a lifestyle adherence score (range 0-8; categorized as low [0-3.74], moderate [3.75-4.74], and high [≥4.75]) was created based on the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations. Cox regression and competing risks analysis were used to analyze the association of adherence to WCRF/AICR lifestyle recommendations with overall mortality and with death due to cardiovascular diseases and cancer, respectively. RESULTS: A total of 8584 women were included (2785 with breast cancer and 5799 without). With a median follow-up of 16.1 years there were 2006 total deaths. Among the deaths of known causes (98.6%), 445 were cardiovascular-related and 1004 were cancer-related. The average lifestyle score was 4.2. There was no differential effect of lifestyle score by case-control status on mortality. After adjusting for covariates, moderate (hazard ratio [HR], 0.66; 95% confidence interval [CI], 0.57-0.76) and high (HR, 0.54; 95% CI, 0.47-0.63) adherence to WCRF/AICR lifestyle recommendations were significantly associated with a decrease in overall mortality. Similarly, in competing risks analysis, moderate and high adherence were associated with decreased mortality from cardiovascular diseases and from cancer. CONCLUSIONS: A healthy lifestyle can substantially reduce mortality risk in women. With low adherence to all WCRF/AICR guidelines in about a third of study participants, health interventions are warranted.

The impact of cardiovascular disease on all-cause and cancer mortality: results from a 16-year follow-up of a German breast cancer case-control study.

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of death worldwide. The aim of this study was to examine if CVD affects the mortality of women after a breast cancer diagnosis and population controls differently. METHODS: The analysis included a total of 3,555 women, diagnosed with primary stage 1-3 breast cancer or in situ carcinoma between 2002 and 2005 and 7,334 controls breast cancer-free at recruitment, all aged 50-74 years, who were followed-up in a German breast cancer case-control study until June, 30 2020. Kaplan-Meier and cumulative incidence function were calculated for all-cause mortality and mortality from any cancer, stratified for case-control status and CVD, separately for women aged < 65 and ≥ 65 years. Cox regression and Fine-Gray subdistribution hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (95% CI) for the association between case-control-status, CVD and mortality from all causes/any cancer. RESULTS: The median follow-up was 16.1 years. In total, 1,172 cases (33.0%) and 1,401 initial controls (19.1%) died. CVD prevalence at recruitment was 15.2% in cases and controls. Cases with CVD had the highest and controls without CVD the lowest mortality during the entire observation period in both age groups (< 65 and ≥ 65 years). CVD was identified as a risk factor for all-cause mortality in both cases and controls aged < 65 years (HR 1.22, 95%CI 0.96-1.55 and HR 1.79, 95%CI 1.43-2.24) as well as at ages of ≥ 65 years (HR 1.44, 95%CI 1.20-1.73 and HR 1.59, 95%CI 1.37-1.83). A significant association of CVD and cancer mortality was found only for cases aged ≥ 65 years. CONCLUSION: CVD was significantly associated with all-cause mortality of both cases and controls and CVD was identified as a risk factor for cancer mortality of cases aged ≥ 65 years at recruitment. Therefore, attention should be paid on monitoring and preventing CVD in breast cancer patients, especially in those diagnosed at older ages.

Device-Aided Therapies in Parkinson's Disease-Results from the German Care4PD Study.

Data on the use of device-aided therapies (DATs) in people with Parkinson's disease (PwP) are scarce. Analyzing data from the Care4PD patient survey, we (1) evaluated application frequency and type of DAT in a larger, nationwide, cross-sectoral PwP sample in Germany; (2) analyzed the frequency of symptoms indicative for advanced PD (aPD) and need for DAT amongst the remaining patients and (3) compared the most bothersome symptoms and need for professional long-term care (LTC) of patients with and without suspected aPD. Data from 1269 PwP were analyzed. In total, 153 PwP (12%) received DAT, mainly deep brain stimulation (DBS). Of the remaining 1116 PwP without DAT, >50% fulfilled at least one aPD criterion. Akinesia/rigidity and autonomic problems were most bothersome for PwP with and without suspected aPD, with more tremor in the non-aPD and more motor fluctuations and falls in the aPD group. To recapitulate, the German DAT application rate is rather low, although a large proportion of PwP fulfills aPD criteria indicating a need for intensified treatment strategies. Many reported bothersome symptoms could be overcome with DAT with benefits even for LTC patients. Thus, precise and early identification of aPD symptoms (and therapy-resistant tremor) should be implemented in future DAT preselection tools and educational trainings.

Changes in cigarette smoking behavior among breast cancer and unaffected women - A prospective study in the MARIE cohort.

BACKGROUND: Smoking cessation after a cancer diagnosis can reduce adverse cancer treatment outcomes. Whether a breast cancer diagnosis, a cancer commonly seen as unrelated to smoking cigarettes, motivates changes in smoking behavior is not fully understood. We aimed to compare long-term changes at three follow-up times of cigarette smoking behavior in women with breast cancer and baseline age- and region-matched unaffected women. METHODS: We used longitudinal data from the population-based case-control study MARIE (Mamma Carcinoma Risk Factor Investigation). Women with breast cancer (N = 3813) and unaffected women (N = 7341) aged 50-74 years were recruited from 2002 to 2005. Analyses on changes in smoking were based on data from those who also completed follow-up 1 in 2009-2012, follow-up 2 in 2014-2016 and follow-up 3 in 2020. Multinomial logistic regression for changes (quitting, stable, or start smoking) adjusted for age, study region, education, comorbidities, living situation, and follow-up time, was applied to examine the associations between breast cancer status and changes in smoking behavior. RESULTS: Women with breast cancer had significantly higher odds than unaffected women of quitting smoking (OR = 1.38, 95 % CI: 1.01-1.89) and lower odds of returning to smoking (OR = 0.29, 95 % CI: 0.09-0.94) at follow-up 1, but were more likely to start or return to smoking at follow-up 2 (OR = 2.11, 95 % CI 1.08-4.15). No significant group differences were found for changes in smoking behavior at follow-up 3. CONCLUSION: Our findings indicate that short-term changes in smoking behavior can be attributed to a breast cancer diagnosis, but that over time the effect diminishes and changes in smoking no longer differ between breast cancer and breast cancer-free women. To support smoking cessation and to prevent relapse, guidelines to address smoking in cancer care, as well as comprehensive tobacco treatment services, are needed.

Comorbidity burden in long-term breast cancer survivors compared with a cohort of population-based controls from the MARIE study.

BACKGROUND: The number of elderly cancer survivors is growing because of increasing survival rates. A high comorbidity burden in the elderly can affect their quality of life and survival. The aim of this study was to examine whether breast cancer survivors and population-based controls have a different comorbidity burden after long-term follow-up. METHODS: This study used data from a German breast cancer case-control study, which initially comprised 3813 breast cancer cases aged 50 to 74 years who were diagnosed between 2002 and 2005 and 7341 population-based controls. Participants were followed up in 2014/2016. A modified Charlson Comorbidity Index (mCCI) was calculated to quantify severe comorbidities. Negative binomial regression was performed to estimate rate ratios (RRs) with 95% confidence intervals (CIs) for the association between case-control status and mCCI (dependent variable) for the baseline population and for those who participated at follow-up, with adjustments made for relevant lifestyle factors. RESULTS: In total, 1925 cases and 3674 controls participated in the follow-up 12 years after recruitment. In the baseline population 35% had at least 1 comorbid condition.In long-term survivors this proportion was 52%. No difference was found in the mCCI between breast cancer cases and controls at baseline (RR, 1.05; 95% CI, 0.98-1.11) or between long-term survivors of the 2 groups at baseline (RR, 1.07; 95% CI, 0.97-1.18) or at follow-up (RR, 1.00; 95% CI, 0.91-1.10). CONCLUSIONS: The comorbidity burden of long-term breast cancer survivors and controls increased over time; however, it remained similar in both groups after 12 years of follow-up.

Changes in alcohol consumption, body weight and physical activity among breast cancer survivors and population-based unaffected women in a prospective study.

BACKGROUND: It is unclear whether a breast cancer diagnosis affects health behaviour changes that occur with ageing. We aimed to compare long-term changes of alcohol consumption, body weight, and physical activity in women with breast cancer and in age-matched unaffected women. METHODS: We used data from 1,925 women with breast cancer and 3,473 unaffected women aged 50-74 years enrolled in the population-based case-control study MARIE (Mamma Carcinoma Risk Factor Investigation) in 2002-2005, who also completed the follow-up in 2014-2016. Multinomial logistic regression was applied to estimate odds ratios (ORs) and 95 % confidence intervals (CIs) for the associations between breast cancer status and categories of change in alcohol consumption, weight and physical activity. RESULTS: After 11.6 years of follow-up, breast cancer survivors had significantly lower odds than unaffected women of increasing alcohol consumption from ≤10 to >10 g/day (adjusted OR 0.48, 95 % CI 0.35-0.65), but were more likely to experience a major weight change of ≥10 % compared to having stable weight (±<5 %) (OR for increase and decrease 1.32, 95 % CI 1.03-1.70 and 1.36, 95 % CI 1.05-1.77, resp.) and to decrease transport physical activity to below 2.5 h/week compared to maintaining the activity level (OR 1.61, 95 % CI 1.26-2.04). No significant group difference was found for changes in recreational physical activity. CONCLUSION: Our data indicate that some long-term health behaviour changes can be attributed to a breast cancer diagnosis rather than ageing, suggesting that long-term medical care of breast cancer survivors could pay greater attention to weight control and sufficient physical activity.