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 Table of Contents  
ORIGINAL ARTICLE
Year : 2014  |  Volume : 1  |  Issue : 4  |  Page : 245-249

Prevalence of possible Alzheimer's disease in an urban elderly population of Ludhiana: A pilot study


Department of Community Medicine, Christian Medical College, Ludhiana, India

Date of Web Publication16-Oct-2014

Correspondence Address:
Dr. Paramita Sengupta
Professor of Community Medicine, Christian Medical College, Ludhiana - 141 008, Punjab
India
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Source of Support: ICMR-STS 2010., Conflict of Interest: None


DOI: 10.4103/2348-3334.142988

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  Abstract 

Background : Dementias in the elderly, of which Alzheimer's disease (AD) is the most common form, may emerge as important public health problems in the elderly in low-resource developing countries whose populations are ageing rapidly. Aims: 1. To find out the prevalence of possible AD in the elderly population of an urban area of Ludhiana. 2. To identify major socio-demographic risk factors for "possible AD" in the population under study. Materials and Methods: A cross-sectional study was conducted on >60 year old residents of an urban area of Ludhiana. Data was collected from 200 consenting individuals chosen by simple random sampling, using a pre-tested questionnaire with standardized batteries, "10 Warning Signs of Alzheimer's Disease" to screen for possible AD, Everyday Abilities Scale for India (EASI) to assess physical impairment and the Hindi version of the Mini-Mental State Examination (MMSE) to assess cognitive impairment. The presence of >1 warning signs was considered as "possible AD", EASI score >3 as "functional impairment" and MMSE score <24 as "cognitive impairment". A respondent with "possible AD" as well as cognitive and functional impairment was labelled as "probable AD". Results: The prevalence of "possible AD" in the study population was 12.0% and "probable AD" 2.0%. Higher age (>80-years-old) was observed to be a significant risk factor for "possible AD" [odd ratio (OR) = 3.93, confidence interval (CI) = 1.10-13.26). Gender, educational status, marital status, family type, employment status, and addictions were not found to be statistically significant risk factors (P > 0.05). One-third of those with "possible AD" had "probable AD". Those with "possible AD" were at high risk of having functional impairment (OR = 17.10, 95%, CI = 5.00-58.46).

Keywords: Alzheimer′s disease, cognitive impairment, dementia, functional impairment, urban elderly


How to cite this article:
Bhatti N, Sengupta P, Benjamin AI. Prevalence of possible Alzheimer's disease in an urban elderly population of Ludhiana: A pilot study. CHRISMED J Health Res 2014;1:245-9

How to cite this URL:
Bhatti N, Sengupta P, Benjamin AI. Prevalence of possible Alzheimer's disease in an urban elderly population of Ludhiana: A pilot study. CHRISMED J Health Res [serial online] 2014 [cited 2019 Oct 21];1:245-9. Available from: http://www.cjhr.org/text.asp?2014/1/4/245/142988


  Introduction Top


Alzheimer's disease (AD) is the most common form of dementia, [1] resulting in an acquired cognitive and behavioral impairment of sufficient severity that markedly interfere with social and occupational functioning. AD and other dementias are already a major public health problem among the elderly in industrialized countries, and could have a devastating impact on developing countries, whose populations are ageing rapidly. By the year 2020, approximately 70% of the world's population aged >60 will be located in developing countries; with 14.2% in India. [2] The frequency of dementia, of which AD is the common form double every 5 years after the age of sixty. [3] Studies of their prevalence rates and determinants are of medical and social importance. Moreover, there is dearth of population-based data from Punjab.

Aims and Objectives

To find out the prevalence and major socio-demographic risk factors for possible AD in an urban elderly population of Ludhiana, Punjab.


  Materials and Methods Top


Study design

Population-based, cross-sectional, descriptive study.

Population under study

The >60 years old residents of the urban field practice area of the Department of Community Medicine of a medical college in Ludhiana constituted the study population. The population covered by the two multipurpose health workers (MPHWs) is 9250, in which the >60-years-old numbers 614 (6.6%) of the population.

Sampling method: Simple random sampling

Sample size and sampling

Due to lack of information on the prevalence of dementia/AD in this population, 50% prevalence was presumed for the purpose of calculation of the minimum sample size required for this study. Hence, using the formula, n = (4pq)/L 2 , where n = the minimum sample size required, P = 50, q = (100-p) and L = 10%, the minimum sample size required at 95% CI was 400. As this was too large a sample for a medical student to study in a short span of Indian Council of Medical Research Short -Term Studentship (ICMR-STS) study the sample size required at 15% allowable error and 95% confidence interval, that is 178, was taken for the study. A total of 200 respondents were actually studied. The respondents were obtained by a computer-generated list of 200 random numbers from a line-listing of the 614 eligible elderly in the population as per the family folder records of the population maintained in the department's database. The sampled elderly so obtained were visited by the investigator along with the MPHW. If any of them refused consent or were found ineligible to be included in the study as per the exclusion criteria, they were replaced by the next elderly on the list.

Exclusion criteria

The hearing and/or speech impaired, those with diagnosed psychiatric illness (schizophrenia, mental retardation), those with history of neurological disorders (stroke, Parkinsonism, epilepsy), and those living alone with no care-giver were excluded, since there was no way to obtain reliable information from them.

Ethics Approval

The study protocol was approved by the Institutional Ethics Committee.

Data collection procedure and instrument

Informed consent was obtained from the respondents either by their signature or, in the case of illiterate respondents, by their thumb impression. Consent was obtained from the attending care-giver in the case of elderly respondents with severe cognitive decline. Initial evaluation of the subjects was carried out using a pre-tested investigator-administered questionnaire containing various socio-demographic parameters, and information was obtained regarding the presence of the 10 warning signs of AD recommended by the Alzheimer's Association. [4] The presence of at least one warning sign being indicative of possible AD. Information from caregivers was also obtained to assess physical functioning of the respondent on EASI [5] scale. Thus, even when subjects were cognitively untestable because of sensory impairment or illness it was possible to obtain functional ability data. Cognitive functioning was assessed by applying the MMSE [6] on respondents who were identified as having "possible AD" on the basis of presence of at least one of the ten warning signs of AD. The Hindi translation of MMSE, validated in north Indian elderly population in a previous study [7] was used in this study. Since all the instruments/questionnaires used were investigator-administered, and did not require the respondent to read or write, they could be used for the illiterate respondents also.

Operational defining criteria

  1. Subjects were classified as "possible Alzheimer's" if they had any one of the ten warning signs of AD. [4]
  2. Subjects were classified as "functionally impaired" based on inability to perform three or more items on EASI Scale. [5]
  3. MMSE score <24 was considered as "cognitively impaired". [6]


If any respondent with "possible AD" was found to be both "functionally impaired" as well as "cognitively impaired" based on EASI score >3 and MMSE score <24, respectively, they would be categorized as "Probable AD" in the present study.

Statistical analysis

The data was compiled and analyzed using Epi-Info v6. Proportions, OR with 95% Confidence Limit, and Chi-square test were used in statistical analysis.


  Results Top


The prevalence of "possible AD" in the population under study, as evidenced by the presence of at least one of the ten warning signs of AD being the criteria recommended by the Alzheimer's Association, was found to be 12.0% [Table 1].
Table 1: Presence of warning signs of Alzheimer's disease in the elderly (n=200)

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Higher age (>80 years) was observed to be a statistically significant risk factor for "possible AD" (OR = 3.93, 95% CI = 1.10-13.26). Gender, educational status, marital status, family type, employment status, and addictions were factors not found to be statistically significant risk factors for "possible AD" (P > 0.05) [Table 2].
Table 2: Socio-demographic risk factors for possible AD

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Thirteen (6.5%) of the respondents had functional impairment with a score of three or more on the EASI scale. The prevalence of functional impairment was 33.3% in those with "possible AD" as compared to 2.8% in those without, and the difference was statistically highly significant (P = 0.000000). Those with "possible AD", therefore, were observed to be at high risk of having functional impairment (OR = 17.10, 95% CI = 5.00-58.46) [Table 3].
Table 3: Functional impairment in the elderly

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Out of the 24 respondents with "possible AD", cognitive impairment (MMSE score <24) was observed in four. All these four respondents also suffered from functional impairment. Hence, the prevalence of "probable AD" in the study population was 2.0%. All four of them also had all the 10 warning signs of AD.

The most common co-morbidities reported amongst those with "possible AD" were hypertension (58.3%) followed by Coronary Artery Disease (16.7%) and Diabetes Mellitus (16.7%).


  Discussion Top


The most common form of dementia is AD, accounting for 60-80% of dementia cases and vascular dementia, which occurs after a stroke, is the second most common form, accounting for about 10% of the cases. [8] We have excluded from our study those with history of stroke, hence, vascular dementia is excluded in our study, leaving AD as being the most likely cause in those found to have dementia.

The prevalence of "possible AD" in the present study (12.0%), based on the presence of at least one out of ten warning signs, is similar to that observed in Uttarakhand [9] (10.0%) using the same criteria and in the same age-group.

Higher age (>80 years) was observed to a statistically significant risk factor for "possible AD" (OR = 3.93, 95% CI = 1.10-13.26, P = 0.04), which is in agreement with the findings of other researchers. [10],[11],[12] Gender, educational status, marital status, family type, employment status, and addictions were factors not found to be statistically significant risk factors for the condition (P > 0.05). Chandra et al., [12] reported higher prevalence of AD in males, but others [9],[10],[11] found the prevalence of AD to be higher among females. The Rotterdam study, [10] found the two lowest educational levels to be associated with increased risk for AD (RR = 4.0, CI = 2.5-6.2, and RR = 2.3, CI = 1.3-4.1, respectively). Cosme et al., [13] found higher prevalence of unemployment amongst those with AD.

Hypertension (58.3%), Coronary Artery Disease (16.7%), and Diabetes Mellitus (16.7%) were the most common reported co-morbidities amongst those with "possible AD". Van den Berg et al., [14] observed that vascular risk factors, such as type 2 diabetes mellitus, hypertension, dyslipidemia and obesity, have an association with an increased risk of cognitive dysfunction, particularly in the elderly. Other researchers [15],[16] have also made similar observations.

Those with "possible AD" were at higher risk of having functional impairment (OR = 17.10, 95% CI = 5.00-58.46). Four out of 24 "possible AD" sufferers had both cognitive as well as functional impairment, thus, the prevalence of "probable AD" was 2.0%. A study in Ballabgarh, [12] also using the Hindi version of MMSE and EASI as well as other batteries reported an overall prevalence of AD in >55 years age-group as 1.36%. Vas et al., [17] found the overall prevalence rate for AD in urban Mumbai as 0.25%, and 1.5% for those aged 65 years and above.

Limitations of the study

Due to time and resource constraints for a student researcher, the sample size in this study is limited and expected to give a larger margin of error. Also, reliance has been placed on a screening test for warning signs of AD carried out in a community setting. However, screening the elderly for AD by using the "10 Warning Signs of Alzheimer's Disease" method has been demonstrated to be a useful tool in the hands of even grass-root level health workers in a community-based study. [18] The diagnosis of AD requires proficiency and expertise of a specialist physician, and imaging is essential if possible dementia has to be diagnosed. There is no single test that can show whether a person has Alzheimer's. While physicians can almost always determine if a person has dementia, it may be difficult to determine the exact cause. Diagnosing Alzheimer's requires careful medical evaluation, including a thorough medical history, mental status testing, a physical and neurological examination and tests such as blood tests and brain imaging to rule out other causes of dementia-like symptoms. Since this was not possible in this population-based field study, having ruled out vascular dementia by excluding respondents with history of stroke, this screening at best can indicate only the possibility of AD.


  Conclusions Top


Twelve percent of the elderly respondents in this study were found to be suffering from "possible AD", and 2.0% from "probable AD". "Possible AD" was significantly associated with higher age. Gender, educational status, marital status, family type, employment status and addictions were not found to be associated with "possible AD". Hypertension was the most common co-morbidity observed among respondents with "possible AD", followed by Coronary Artery Disease and Diabetes Mellitus. Those with "possible AD" were at very high risk of having functional impairment.

Efforts to improve the quality and availability of care, as well as to find more effective treatments for Alzheimer's and other dementias, should be coupled with urgent investment in primary disease prevention measures. The provision and financing of measures to meet the long term care needs of people with Alzheimer's or other dementias, including support for their family caregivers, is an increasingly urgent priority. The health and social care needs of the large and rapidly growing number of the elderly should be a matter of concern, and included in the national primary health care system.

 
  References Top

1.
Plassman BL, Langa KM, Fisher GG, Heeringa SG, Weir DR, Ofstedal MB, et al. Prevalence of dementia in the United States: The ageing demographics and memory study. Neuroepidemiology 2007;29:125-32.  Back to cited text no. 1
    
2.
WHO: Population ageing, a public health challenge. Fact Sheet no. 135, Geneva: WHO; 1998.  Back to cited text no. 2
    
3.
Development in mental health scenario: Need to stop exclusion - dare to care. ICMR Bulletin 2001;31:4.  Back to cited text no. 3
    
4.
Alzheimer′s Association. 2009. Alzheimer′s disease. Available from: http://www.alz.org. [Last accessed on 2009 Feb 07].  Back to cited text no. 4
    
5.
Fillenbaum GG, Chandra V, Ganguli M, Pandav R, Gilby JE, Seaberg EC, et al. Development of an activities of daily living scale to screen for dementia in an illiterate rural older population in India. Age Ageing 1999;28:161-8.  Back to cited text no. 5
    
6.
Folstein MF, Folstein SE, McHugh PR. ′Mini Mental State′. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res 1975;12:189-98.  Back to cited text no. 6
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7.
Ganguli M, Ratcliff G, Chandra V, Sharma S, Gilby J, Pandav R, et al. A Hindi version of the MMSE: The development of a cognitive screening instrument for a largely illiterate rural elderly population in India. Int J Geriatr Psychiatry 1995;10:367-7.  Back to cited text no. 7
    
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Sengupta P, Singh R, Singh R, Benjamin AI. Prevalence and profile of possible Alzheimer′s Disease in Tehri Garhwal, Uttarakhand. Indian J Gerontol 2010;24:3.  Back to cited text no. 9
    
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Ott A, Breteler MM, van Harskamp F, Claus JJ, van der Cammen TJ, Grobbee DE, et al. Prevalence of Alzheimer′s disease and vascular dementia: Association with education. The Rotterdam Study. BMJ 1995;310:970-3.  Back to cited text no. 10
    
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Shaji S, Bose S, Verghese A. Prevalence of dementia in an urban population in Kerala, India. Br J Psychiatry 2005;186:136-40.  Back to cited text no. 11
    
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Chandra V, Ganguli M, Pandav R, Johnston J, Belle S, DeKosky ST. Prevalence of Alzheimer′s disease and other dementias in rural India. Neurology 1998;51:1000-8.  Back to cited text no. 12
    
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Alvarado-Esquivel C, Hernández-Alvarado AB, Tapia-Rodríguez RO, Guerrero-Iturbe A, Rodríguez-Corral K, Martínez SE. Prevalence of dementia and Alzheimer′s disease in elders of nursing homes and a senior center of Durango City, Mexico. BMC Psychiatry 2004;4:3.  Back to cited text no. 13
    
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van den Berg E, Kloppenborg RP, Kessels RP, Kappelle LJ, Biessels GJ. Type 2 diabetes mellitus, hypertension, dyslipidemia and obesity: A systematic comparison of their impact on cognition. Biochim Biophys Acta 2009;1792:470-81.  Back to cited text no. 14
    
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Luchsinger JA, Reitz C, Honig LS, Tang MX, Shea S, Mayeux R. Aggregation of vascular risk factors and risk of incident Alzheimer disease. Neurology 2005;65:545-51.  Back to cited text no. 16
    
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Vas CJ, Pinto C, Panikker D, Noronha S, Deshpande N, Kulkarni L, et al. Prevalence of dementia in an urban Indian population. Int Psychogeriatr 2001;13:439-50.  Back to cited text no. 17
    
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  [Table 1], [Table 2], [Table 3]



 

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