The use of remote health care services, or telehealth, is a promising solution for providing health care to those unable to access care in person easily and thus helping to reduce health inequalities. The COVID-19 pandemic and resulting stay-at-home orders in the United States have created an optimal situation for the use of telehealth services for non-life-threatening health care use. A retrospective cohort study was performed using Kantar's ClaritisÔ database, which links insurance claims encounters (Komodo Health) with patient-reported data (Kantar Health, National Health & Wellness Survey). Logistic regression models (odds ratios [OR], 95% confidence intervals [CI]) examined predictors of telehealth versus in-person encounters. Adults ages ‡18 years eligible for payer-complete health care encounters in both March 2019 and March 2020 were identified (n = 35,376). Telehealth use increased from 0.2% in 2019 to 1.9% in 2020. In adjusted models of respondents with ‡1 health care encounter (n = 11,614), age, marital status, geographic residence (region; urban/rural), and presence of anxiety or depression were significant predictors of telehealth compared with in-person use in March 2020. For example, adults 45-46 years versus 18-44 years were less likely to use telehealth (OR 0.684, 95% CI: 0.561-0.834), and respondents living in urban versus rural areas were more likely to use telehealth (OR 1.543, 95% CI: 1.153-2.067). Substantial increases in telehealth use were observed during the onset of the COVID-19 pandemic in the United States; however, disparities existed. These inequalities represent the baseline landscape that population health management must monitor and address during this pandemic.

PurposeHormone replacement therapy (HRT) use increases breast cancer risk and mammographic density (MD). We examine whether MD mediates or modifies the association of HRT with the breast cancer.MethodsFor the 4,501 participants in the Danish diet, cancer and health cohort (1993–1997) who attended mammographic screening in Copenhagen (1993–2001), MD (mixed/dense or fatty) was assessed at the first screening after cohort entry. HRT use was assessed by questionnaire and breast cancer diagnoses until 2012 obtained from the Danish cancer registry. The associations of HRT with MD and with breast cancer were analyzed separately using Cox’s regression. Mediation analyses were used to estimate proportion [with 95% confidence intervals (CI)] of an association between HRT and breast cancer mediated by MD.Results2,444 (54.3%) women had mixed/dense breasts, 229 (5.4%) developed breast cancer, and 35.9% were current HRT users at enrollment. Compared to never users, current HRT use was statistically significantly associated with having mixed/dense breasts (relative risk and 95% CI 1.24; 1.14–1.35), and higher risk of breast cancer (hazard ratio 1.87; 1.40–2.48). Association between current HRT use and breast cancer risk was partially mediated by MD (percent mediated = 10%; 95% CI 4–22%). The current HRT use-related breast cancer risk was higher in women with mixed/dense (1.94; 1.37–3.87) than fatty (1.37; 0.80–2.35) breasts (p value for interaction = 0.15).ConclusionsMD partially mediates some of the association between HRT and breast cancer risk. The association between HRT and breast cancer seems to be stronger in women with dense breasts.

BackgroundGrowing evidence suggests that air pollution may be a risk factor for breast cancer, but the biological mechanism remains unknown. High mammographic density (MD) is one of the strongest predictors and biomarkers of breast cancer risk, but it has yet to be linked to air pollution. We investigated the association between long-term exposure to traffic-related air pollution and MD in a prospective cohort of women 50 years and older.MethodsFor the 4,769 women (3,930 postmenopausal) participants in the Danish Diet, Cancer and Health cohort (1993–1997) who attended mammographic screening in Copenhagen (1993–2001), we used MD assessed at the first screening after cohort entry. MD was defined as mixed/dense or fatty. Traffic-related air pollution at residence was assessed by modeled levels of nitrogen oxides (NOx) and nitrogen dioxide (NO2). The association between mean NOx and NO2 levels since 1971 until cohort baseline (1993–97) and MD was analyzed using logistic regression, adjusting for confounders, and separately by menopause, smoking status, and obesity.ResultsWe found inverse, statistically borderline significant associations between long-term exposure to air pollution and having mixed/dense MD in our fully adjusted model (OR; 95% CI: 0.96; 0.93-1.01 per 20 μg/m3 of NOx and 0.89; 0.80- 0.98 per 10 μg/m3 of NO2). There was no interaction with menopause, smoking, or obesity.ConclusionTraffic-related air pollution exposure does not increase MD, indicating that if air pollution increases breast cancer risk, it is not via MD.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-015-0017-8) contains supplementary material, which is available to authorized users.