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Keywords:

  • dementia;
  • prevalence;
  • Caribbean region;
  • Jamaica

Abstract

  1. Top of page
  2. Abstract
  3. Materials and methods
  4. Results
  5. Discussion
  6. Acknowledgement
  7. Conflicts of interest
  8. References

Objectives

Using a cross-sectional community survey, the authors aimed to estimate the prevalence of dementia among a sample of older Jamaicans and to identify associated demographic factors.

Methods

From February to July 2010, persons of age ≥60 years were randomly selected from two communities in Kingston, Jamaica and screened with the Mini Mental Status Examination (MMSE). All MMSE-positive participants and an equal number of matched MMSE-negative participants underwent definitive diagnostic evaluation for dementia using the Clinical and Diagnostic Assessment Procedure for Dementia. Subsequently derived MMSE sensitivity and specificity measures from the subsample were used to estimate the overall prevalence of dementia (primary outcome). Chi square, Fisher's Exact, Exact, Spearman's correlation and t-tests were used to explore associations of dementia with age, gender, educational level and socioeconomic status. Statistical significance was taken as p < 0.05.

Results

Two hundred participants were recruited. Age-standardized prevalence rates of dementia were 5.07% (standardized to the Jamaican population) and 5.32% (standardized to the West Europe population). Dementia was more prevalent among older persons (Spearman's rho = 0.31; p < 0.001); no other significant associations were found.

Conclusions

Dementia prevalence found in this study is lower than figures from previous Caribbean reports. The older persons are disproportionately affected. Copyright © 2013 John Wiley & Sons, Ltd.

The Caribbean reportedly has one of the highest prevalence rates of dementia worldwide (8.12% among persons 60 years of age and older standardized to the West Europe population) (Alzheimer's Disease International 2009). However, the applicability of this high prevalence to the entire region is questionable given the fact that only a small number of dementia prevalence studies have been conducted in the Caribbean and that these have all been carried out in Hispanic Caribbean countries.

Jamaica is an Anglophone Caribbean nation that falls into the category of lower and middle income countries (LAMICs). Because LAMICs are disproportionately affected by the burden of disease associated with dementia (Alzheimer's Disease International 2009), research that seeks to establish actual prevalence and determine associated factors is particularly important.

We hypothesized that the prevalence of dementia among a community sample in Jamaica would be lower than that observed in the Hispanic Caribbean and that there would be higher levels of dementia with increasing age, female gender, lower educational level and lower socioeconomic status.

Materials and methods

  1. Top of page
  2. Abstract
  3. Materials and methods
  4. Results
  5. Discussion
  6. Acknowledgement
  7. Conflicts of interest
  8. References

Ethical approval was obtained from the ethics committee of the authors' university.

From February to July 2010, 100 participants each were randomly selected from the low- and middle-income urban communities of August Town and Mona Heights, respectively; both areas are found in Kingston, Jamaica.

Participants were aged 60 years and over and were evaluated with the Mini Mental Status Examination (MMSE) (Folstein, Folstein et al. 1975). Each person who screened positive on the MMSE (score <24) was matched (according to age, gender and community of domicile) with a participant who screened negative. Both sets of participants subsequently underwent diagnostic evaluation for dementia using the DSM-IV-TR diagnostic criteria (American Psychiatric Association 2000).

Relationships among dementia, age, gender, educational level and socioeconomic status were analyzed using Exact tests and Spearman's correlation.

The crude prevalence rate of dementia was age-standardized to both the West Europe population (indirect method) and Jamaican population (direct method).

Results

  1. Top of page
  2. Abstract
  3. Materials and methods
  4. Results
  5. Discussion
  6. Acknowledgement
  7. Conflicts of interest
  8. References

Of the 200 participants (M:F = 55:100; age range 60–100 years, mean age ± SD = 74 ± 9 years), 28 screened positive on the MMSE. Of these 28 persons, three were lost to follow-up as two had moved out of their community and one refused to participate further. This left 25 MMSE screen positives, all of whom underwent DSM-IV-TR diagnostic evaluation together with 25 matched MMSE screen negatives.

Of all 50 persons undergoing diagnostic evaluation (25 screen positives and 25 screen negatives), 13 cases of dementia were identified, and all 13 cases had been MMSE screen positive. This indicated a 100% sensitivity of the MMSE in this study (i.e., there were no false negatives). Further analyses in this study were based on the premise that there were no false negatives for dementia in the total sample. This implied that among the 200 persons studied, a total of 13 persons had dementia.

The crude prevalence of dementia was 6.5% for the total sample. Age-standardized prevalence rates were 5.32% with reference to the West Europe population and 5.07% with reference to the Jamaican general population (Table 1).

Table 1. Prevalence of dementia (including age-standardized rates) from a community survey in Kingston, Jamaica in 2010
Age group (years)GenderCases of dementiaAge-specific prevalenceStandardization to Jamaican populationaStandardization to W. Europe populationb
 MaleFemaleTotalMaleFemaleTotalMaleFemaleTotalJamaica populationExpected dementia casesW. Europe prevalenceExpected dementia cases
 nnnnnn%%%   %
  1. a

    Age-standardized prevalence rate (to Jamaican population) = expected cases/total population = 15,055.7/296,811 = 5.07%.

  2. b

    SMR (with reference to W. Europe population) = observed cases/expected cases = 13/16.923 = 0.768. Age-standardized prevalence rate (to W. Europe population) = SMR X W. Europe rate = 0.768 X 6.92% = 5.32%.

60–6414264000000068,44501.60.640
65–6911203100000065,09602.60.806
70–749273601103.702.7859,3691649.14.31.548
≥75375693661216.2210.7112.9010,390113,406.6  
75–791521361016.6602.78  7.42.664
80–8418143222411.1114.2812.50  12.94.128
≥854212534775.0019.0428.00    
85–893141723566.6721.4329.41  21.73.689
≥90178112100.0014.2925.00  43.13.448
Total7112920067138.455.436.50296,81115,055.76.9216.923

Higher dementia prevalence was observed as age increased (Spearman's rho = 0.31, p < 0.001) (Table 1). However, no association was found between dementia status and gender (Fisher's Exact Test: p = 0.550), level of education (Exact test: p = 0.464) or socioeconomic status (Fisher's Exact Test: p = 0.082).

Discussion

  1. Top of page
  2. Abstract
  3. Materials and methods
  4. Results
  5. Discussion
  6. Acknowledgement
  7. Conflicts of interest
  8. References

Dementia prevalence among our sample was lower than figures reported on the Hispanic Caribbean. Lower life expectancy in Jamaica, as compared with Hispanic Caribbean countries for which dementia prevalence rates were available (World Health Organization 2011), may have contributed to this finding.

The oldest of Jamaica's elderly would appear to be particularly vulnerable to dementia. The absence of associations between dementia and gender, educational level and socioeconomic status may have been related to our small sample size. In addition, our use of community of residence as a proxy for socioeconomic status may not have been applicable to all participants. Another limitation is that our sample may not have been representative of the general population.

Key points

  • The dementia prevalence rate in our Jamaican sample (standardized to the West Europe population) was 5.32%.
  • A lower prevalence rate of dementia was found in our Jamaican sample than has been reported for the Hispanic Caribbean.
  • The dementia prevalence rate found in our Jamaican sample was comparable to rates reported in other lower and middle income countries.
  • The oldest of Jamaica's elderly would appear to be particularly vulnerable to dementia.

Acknowledgement

  1. Top of page
  2. Abstract
  3. Materials and methods
  4. Results
  5. Discussion
  6. Acknowledgement
  7. Conflicts of interest
  8. References

This study was funded through a New Initiative Grant from the Office of the Principal, The University of the West Indies, Mona Campus.

References

  1. Top of page
  2. Abstract
  3. Materials and methods
  4. Results
  5. Discussion
  6. Acknowledgement
  7. Conflicts of interest
  8. References
  • Alzheimer's Disease International (2009). World Alzheimer Report 2009. M. Prince and J. Jackson. London, Alzheimer's Disease International.
  • American Psychiatric Association (2000). Diagnostic and Statistical Manual of Mental Disorders: DSM-IV-TR. Washington, American Psychiatric Association.
  • World Health Organization (2011). World Health Statistics 2011. Geneva, World Health Organization.