varies with age: Alzheimer’s disease is unco mmon before age 60 years, and the prevalence
increases steeply thereafter, while the overa ll less common frontotemporal lobar degener-
ation has earlier onset and represents a progre ssively smaller fraction of NCDs with age. 
Genetic and physiological. The strongest risk factor for major and mild NCDs is age,
primarily because age increases the risk of  neurodegenerative and cerebrovascular dis-
ease. Female gender is associat ed with higher prevalence of dementia overall, and especially
Alzheimer’s disease, but this difference is larg ely, if not wholly, attr ibutable to greater lon-
gevity in females. 
Culture-Related Diagnostic Issues
Individuals’ and families’ level of awareness and concern about neurocognitive symp-
toms may vary across ethnic and occupational groups. Neurocognitive symptoms are
more likely to be noticed, particularly at the mild level, in individuals who engage in com-
plex occupational, domestic, or recreational activities. In addition , norms for neuropsy-
chological testing tend to be available only for broad populations, and thus they may not
be easily applicable to individuals with less  than high school ed ucation or those being
evaluated outside their primary language or culture. 
Gender-Related Diagnostic Issues
Like age, culture, and occupa tion, gender issues may affect the level of concern and aware-
ness of cognitive symptoms. In addition, for la te-life NCDs, females are likely to be older,
to have more medical comorbidity, and to liv e alone, which can complicate evaluation and
treatment. In addition, there are gender differ ences in the frequency of some of the etio-
logical subtypes.
Diagnostic Markers