Breast cancer screening less common for women with intellectual disability

Among women eligible for Denmark’s national breast cancer screening program, those who had an intellectual disability were less likely to undergo recommended screening, according to findings published in JAMA Network Open.

Women with intellectual disability have greater overall and breast cancer-specific mortality compared with women who do not have an intellectual disability, according to study background. Previous studies have also demonstrated lower screening rates among women with vs. without intellectual disability, but no studies have assessed that rate in Denmark, where participation in the national screening program is high.

“The Danish health care system is tax-financed, and all citizens have universal access to free health care services, including cancer screening,” Trine Allerslev Horsbøl, PhD, an assistant professor of public health epidemiology at the University of Southern Denmark in Copenhagen, and colleagues wrote. “Thus, it is an ideal setting to evaluate participation independently of barriers caused by income and access to health care insurance.”

Methods

Horsbøl and colleagues assessed women’s participation in the Danish national breast cancer screening program from initiation in 2007 until the first censoring event occurred. Censoring events included death, diagnosis of carcinoma in situ or breast cancer and end of the study period on March 31, 2021.

Women entered the study when aged 50 to 69 years until 2017, so women born between 1941 and 1967 were eligible for inclusion. All women were invited to participate in screening every 2 years.

The researchers used the Danish National Patient Register, the Danish Psychiatric Central Research Register and the Danish Cerebral Palsy Registry to identify 5,595 women with intellectual disability, which was defined as diagnosis of intellectual disability; cerebral palsy with intellectual disability; Down syndrome; and/or certain metabolic disorders, congenital malformations and/or chromosomal disorders likely to result in intellectual disability.

Women whose permanent residences were institutions for people with intellectual disability were also included. Some women were included in more than one of these groups.

Women with intellectual disability were age-matched to 49,423 women without intellectual disability.

Findings

Most (82%) women in the intellectual disability group had a diagnosis of intellectual disability, followed by Down syndrome (10%), cerebral palsy with intellectual disability (4%), metabolic disorders (2%) and congenital malformation and/or chromosomal disorders (1%). Also, 30% of women with intellectual disability were found through institutions.

Overall, 1,425 (25%) women with intellectual disability and 30,480 (62%) women without intellectual disability met screening guidelines. Women with intellectual disability were nearly five times more likely to never be screened compared with those who did not have an intellectual disability (45% vs. 13%; adjusted OR = 4.9; 95% CI, 4.6-5.22).

Subgroup analysis

Among women with intellectual disability, those with Down syndrome had the lowest rate of fully adhering to screening recommendations (n = 78; 14%) and those with cerebral palsy with intellectual disability (n = 32; 16%). Women in both subgroups were nearly 11 times as likely to never be screened vs. women with no intellectual disability (aOR for Down syndrome = 10.98; 95% CI, 8.95-13.47; aOR for cerebral palsy = 11.31; 95% CI, 7.99-16.01).

Additionally, the likelihood of never being screened increased with severity of intellectual disability diagnosis. In adjusted analyses, women with mild intellectual disability were three times as likely to never be screened (aOR = 3.36; 95% CI, 3.05-3.7) and those with profound intellectual disability were more than 30 times as likely to never be screened (aOR = 31.28; 95% CI, 21.98-44.52) vs. women without intellectual disability.

“These findings suggest a need for studies focusing on barriers and facilitators for participating in breast cancer screening in a Danish setting among women with intellectual disability,” Horsbøl and colleagues wrote. “Such knowledge could facilitate tailored guidelines and approaches for breast cancer screening in this group of women.”