Increasing cancer risk over calendar year in people with multiple sclerosis: a case–control study

Background Data on cancer prevalence and incidence in multiple sclerosis (MS) patients are controversial. This study is aimed at estimating cancer risk in MS patients. Methods Nested case–control study using data collected between 01/01/1987 and 28/02/2016 from the United Kingdom Clinical Practice Research Datalink. Cancer diagnoses after first MS code (index date) was counted in 10,204 MS patients and 39,448 controls matched by sex, age, general practitioner, and registration year. Cancer rates were compared using multivariable Cox regression models. Ethics approval was not required. Results Cancer was reported in 433 (4.41%) MS patients and 2014 (5.31%) controls after index date. Cancer risk was associated with gender (HR for female = 0.88, 95% CI = 0.81–0.96, p = 0.004), age at index date (HR = 1.06, 95% CI = 1.06–1.07, p