Use of latent class analyses for the estimation of prevalence of cognitive impairment, and signs of stroke and Parkinson's disease among African-American elderly of central Harlem: results of the Harlem Aging Project.

A probability sample (response rate of 79.4%) of 164 African-American elderly residing in central Harlem was assessed using several standard cognitive screening measures and scales measuring stroke and Parkinson's symptoms, respectively. Both traditional cutting scores and the methods of latent class analysis were used to estimate point prevalence. The latent class prevalence ratio estimates range from 10 to 14%. The confidence intervals for cognitive impairment ranged from 5 to 18% with an average estimate of 12%. The latent class estimate for stroke effects was 11% and for two measures of neurological signs associated with Parkinson's disease 7 and 12%. About 2-3% of the sample were communication disordered, and 5% had significant ambulation disorder. These results indicate that a relatively large proportion of elderly community residents of central Harlem evidenced or reported health problems, any or all of which may constitute a public health challenge.