The incidence rate of a disease is 5 times greater in women than in men, but the prevalence rates show no sex difference. The best explanation is that:
Prevalence depends upon 2 factors, the incidence and duration of illness. Given the assumption that the population is stable, and  incidence and duration are unchanging, the relationship between incidence and prevalence can be expressed as: 
Prevalence = Incidence x  Mean duration 
Note:
In the given question, if incidence for a disease is 5 times higher among females, but prevalence rate shows no sex difference, since P = I × d, thus, d (duration of disease) must be lower among females.

Either the disease is more fatal among females or
Disease is easily curable among females.
The case fatality rate for this disease is lower in women
The case fatality rate for this disease is higher for women
The duration of disease is shorter in men
Risk factors for developing the disease are more common in women