The burden of chronic lymphocytic leukaemia (CLL) is expected to grow in both men and women, ages 18 years and older, between 2015 and 2025 in the seven major markets (7MM: US, France, Germany, Italy, Spain, UK, and Canada). GlobalData epidemiologists forecast an increase in the number of diagnosed incident cases, most notably in men. Figure 1 presents the sex-specific cases of CLL in the 7MM in 2015.

CLL is a type of cancer in which the bone marrow makes too many lymphocytes. CLL affects a particular lymphocyte, the B cell, which accumulates mainly in the bone marrow and blood, and normally fights infection. In CLL, the DNA of a B cell is damaged so that it cannot fight infection, but instead, it grows out of control and negatively impacts the body’s immune system.

The causes of CLL are largely unknown, but researchers believe that certain non-modifiable factors such as age, sex, race, and family history, and modifiable factors such as exposure to chemicals, may increase the risk of developing CLL. CLL is primarily a disease of the elderly population, with less than 10% of the cases below 40 years of age. CLL accounts for 30% of all adult leukaemia cases and is the most common form of leukaemia in the Western world, with prevalence in men considerably higher than in women.

GlobalData Epidemiologists calculated that the majority of diagnosed incident cases of CLL in the 7MM, in 2015, occurred in men, with 24,952 cases (61.41%), while women accounted for 38.59% with 15,679 cases. The greatest disparity was seen in the US, where the number of cases in men was much higher than in other markets, with 10,830 diagnosed incident cases, while women accounted for 6,958 cases. The most even burden of CLL was in Spain and Italy, where 60.1% of cases (1,114 and 1,651, respectively) were in men.

There is no definitive explanation for the higher prevalence of CLL in men. However, the differences in the numbers of diagnosed incident cases of CLL across the sexes and markets may be mostly attributed to differences in the underlying demographic differences in each market as well as the significant differences in sex-specific diagnosed incidence.