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Keywords:

  • IADL;
  • handgrip strength;
  • oral self-care;
  • old people

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

doi: 10.1111/j.1741-2358.2010.00427.x

Associations of instrumental activities of daily living and handgrip strength with oral self-care among home-dwelling elderly 75+

Objective:  To study the associations of instrumental activities of daily living (IADL) and the handgrip strength with oral self-care among dentate home-dwelling elderly people in Finland.

Materials and methods:  The study analysed data for 168 dentate participants (mean age 80.6 years) in the population-based Geriatric Multidisciplinary Strategy for Good Care of the Elderly (GeMS) study. Each participant received a clinical oral examination and structured interview in 2004–2005. Functional status was assessed using the IADL scale and handgrip strength was measured using handheld dynamometry.

Results:  Study participants with high IADL (scores 7–8) had odds ratios (ORs) for brushing their teeth at least twice a day of 2.7 [95% confidence intervals (CI) 1.1–6.8], for using toothpaste at least twice a day of 2.0 (CI 0.8–5.2) and for having good oral hygiene of 2.8 (CI 1.0–8.3) when compared with participants with low IADL (scores ≤6). Participants in the upper tertiles of the handgrip strength had ORs for brushing the teeth at least twice a day of 0.9 (CI 0.4–1.9), for using the toothpaste at least twice a day of 0.9 (CI 0.4–1.8) and for good oral hygiene of 1.1 (CI 0.5–2.4) in comparison with the study subjects in the lowest tertile of handgrip strength.

Conclusion:  The results of this study suggest that the functional status, measured by means of the IADL scale, but not handgrip strength, is an important determinant of oral self-care among the home-dwelling elderly.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

A large and increasing proportion of elderly people are dentate1. This has created new dental health care challenges. These challenges include maintaining the oral hygiene of elderly people, especially those with impaired functional abilities, and identifying and assisting elderly people at risk of inadequate oral self-care2.

With advancing age, a larger proportion of elderly people experience difficulties performing everyday tasks. The instrumental activities of daily living (IADL) scale, developed by Lawton and Brody3, has been used to measure functional status related to performing daily activities. The IADL scale has been used to measure the capacity of elderly people for self-care and independence. Previous studies have reported that some items in the IADL scale are associated with chewing ability4,5, tooth loss and caries6. However, the possible association between IADL scores and oral self-care is not known.

Handgrip strength has been used as an indicator of overall muscle strength. Decline in muscle strength is a risk for functional limitations7. There is an almost linear decline in grip strength between the ages of 50 and 858. In previous studies, the decline in handgrip strength over a 5-year period among 80 year old people was associated with the presence of periodontitis9 but not edentulism10. In institutional care, the association between poor hand function or impaired hand dexterity and poor plaque removal have been observed11,12. However, little is known about the possible relation of hand grip strength to oral self-care.

Adequate plaque control is important in the treatment of oral diseases13,14, including among the elderly15. Knowledge about factors related to oral self-care and plaque removal among the home-dwelling elderly is scarce compared to knowledge among the institutionalised elderly16–18. This is despite the fact that home-dwelling elderly comprise the majority of the elderly population19. The objective of this cross-sectional study was to investigate the associations of the IADL and the handgrip strength with oral self-care among a random sample of dentate home-dwelling elderly people in Finland. The specific objectives were to investigate the association of IADL and handgrip strength with toothbrushing frequency, toothpaste use frequency and oral hygiene.

Materials and methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

Study population

This study was based on a sample of 168 (116 females, 52 males) dentate home-dwelling elderly people, mean age 80.6 (SD 3.6) years, who were participants in the population-based Geriatric Multidisciplinary Strategy for the Good Care of the Elderly (GeMS)study. The GeMS study was a randomised comparative study which evaluated a model for geriatric assessment, care and rehabilitation. The study sample (n = 1000) was randomly selected from all persons aged ≥75 years (born before 1 November, 1928) living in the City of Kuopio, Finland20. Five hundred people were randomised into the intervention group and 500 people into the comparison group. In total, 781 persons provided written informed consent to participate (162 persons refused participation, two persons had moved residence, and 55 persons died before the scheduled baseline examination). According to the study protocol, an oral examination was only performed for consenting participants in the intervention group (n = 404). A clinical oral examination was performed for 354 participants (27 refused, 23 died before the oral examination) in 2004–2005. After restriction to home-dwelling dentate subjects the final study sample consisted of 168 subjects.

Clinical oral examination

The structured interview and clinical oral examination was performed by two dentists at the clinic of the social and health centre of Kuopio or in person’s home. Thirty-two of the study participants (19%) were unable to visit the clinic or they indicated their preference to receive a home visit.

The clinical oral examinations were performed in a standardised manner according to a pre-agreed written protocol. At the start of the study the two dentists examined seven study participants together at the dental clinic to standardise their examination procedure. The first seven persons on the id-number list, who could accept the appointment, were selected for the calibration procedure. Due to the age of the study participants and the length of time required to examine one participant (approximately 1 h) repeated oral examinations were not performed.

Outcome variables

In this study there were three outcome variables: toothbrushing frequency, toothpaste use and oral hygiene. Toothbrushing frequency and toothpaste use were categorised into two groups: at least twice a day or less than twice a day. Oral hygiene was measured according to the presence of dental plaque, recorded on buccal and palatal/lingual surfaces of each tooth in the following manner: (i) no plaque, (ii) plaque in the gingival margin, (iii) plaque elsewhere. This variable was categorised as those with dental plaque in 0–20% of teeth (on any surface) vs. those with dental plaque in more than 20% of all teeth.

Explanatory variables and potential confounding factors

The main explanatory variables were IADL scores and handgrip strength measured by a handheld dynamometer test. The IADL scale included the eight following activities: using the telephone, shopping for groceries, preparing food, housekeeping, doing laundry, using public transportation, being responsible for own medicine and handling personal finances. The participant was asked, whether he/she was capable of doing the activity even though he/she did not do that. The sum of the scores varied from 0 to 8, mean 7.0 (SD 1.5), with higher scores indicating better functional status. The IADL scores were categorised into two groups based on the mean value: scores 0–6 (low) vs. 7–8 (high).

The study physiotherapist measured the handgrip strength using the Saehan-dynamometer. Grip strength was measured in a seated position with the elbow flexed 90°, twice for each hand. The result (the higher value of the two measurements) of the stronger hand was used this study. The classification of the hand grip strength was made by the lowest tertile vs. the upper two tertiles and by gender and age groups. For females aged 75–79 years the mean grip strength was 22.6 kg (SD 5.6) and the limit for lowest tertile was 20.0 kg or less. For females aged 80 years or older the mean grip strength was 17.9 kg and the limit of the lowest tertile was 17 kg or less. For males aged 75–79 years the mean grip strength was 35.9 kg (SD 10.4) and the limit of the lowest tertile was 32.0 kg or less. For males aged 80 years or older the mean grip strength was 31.9 kg and the limit of the lowest tertile was 29.0 kg or less.

The study nurse assessed cognitive function using the Mini-Mental State Examination (MMSE)21. In the present study, the mean MMSE score was 27.0 (SD 3.8). MMSE scores were categorised based on the mean value as 0–26 vs. 27–30.

The other variables were gender, age, education (≥7 vs. less), self-reported feeling of dry mouth (Yes/No) and whether the participants had their own dentist (Yes/No). The study participant was considered dentate if she/he had at least one clinically visible tooth. The number of teeth was categorised 1–9, 10–19 and ≥20. The basic characteristics of the study population are shown in Table 1.

Table 1.   Basic characteristics of the study population, proportions (%) or means (SD) in different categories of IADLa score and handgrip strength.
  All n = 168 IADL (n = 167) Handgrip strength (n = 165)
score 7–8 n = 129 score≤6 n = 38 upper tertiles n = 110 lowest tertile n = 55
  1. aInstrumental Activities of Daily Living.

  2. bMini-Mental State Examination.

Age, years mean (SD)80.6 (3.6)80.1 (3.3)82.0 (4.4)80.3 (3.3)81.2 (4.3)
 75–79 years (%)92/168 (53.6)76/129 (58.8)14/38 (36.8)60/110 (54.5)28/55 (50.9)
Gender, female (%)116/168 (69.0)95/129 (73.6)20/38 (52.6)78/110 (70.9)36/55 (65.5)
Education 7 years or more (%)92/165 (54.8)73/126 (57.9)8/38 (36.8)64/108 (59.3)27/54 (50.0)
Number of teeth, mean (SD)14.4 (8.1)15.2 (8.1)12.3 (7.7)15.0 (7.6)13.6 (9.0)
 ≥20 (%)60/168 (35.7)51/129 (39.5)9/38 (23.7)41/110 (37.5)19/55 (34.5)
 10–19 (%)42/168 (28.0)31/129 (24.0)11/38 (28.9)32/110 (29.1)10/55 (18.2)
 < 10 (%)66/168 (39.3)47/129 (36.4)18/38 (47.4)37/110 (33.4)26/55 (47.3)
Toothbrushing at least twice a day (%)116/168 (69.0)98/129 (76.0)17/38 (44.7)78/110 (70.9)37/55 (67.3)
Toothpaste use at least twice a day (%)81/168 (48.2)71/129 (55.0)10/38 (26.3)55/110 (50.0)25/55 (45.5)
Good oral hygiene (%)56/168 (33.3)50/129 (38.8)6/38 (15.8)40/110 (36.4)16/55 (29.1)
Has ‘own’ dentist (%)90/167 (53.1)72/128 (56.3)17/38 (44.7)63/109 (57.8)26/55 (47.3)
Has feeling of dry mouth (%)83/168 (49.4)66/129 (51.2)17/38 (44.7)55/110 (50.0)28/55 (50.5)
MMSEb (0–30) mean (SD)27.0 (3.8)28.0 (2.3)23.1 (2.3)28.0 (2.3)25.9 (4.3)
 score 27–30 (%)111/168 (66.1)97/129 (75.2)13/38 (34.2)80/110 (72.7)30/55 (54.5)
IADLa (0–8) mean (SD)7.0 (1.5)7.7 (0.5)4.6 (1.5)7.5 (0.9)6.2 (2.0)

Statistical methods

Odds ratios (OR) with 95% confidence intervals (CI) were estimated using logistic regression models. The selection of potential confounders was based on the current knowledge about the factors that could confound the association between IADL and the handgrip strength with oral self-care (Tables 1–3). These were gender, age, education, number of teeth, feeling of dry mouth, having own dentist and cognitive status (MMSE). The statistical analyses were performed using spss 14.0 for Windows (SPSS, Chicago, IL, USA).

Table 2.   Factors associated with toothbrushing frequency and toothpaste use.
  Toothbrushing at least twice a day Toothpaste use at least twice a day
n = 116 (%) OR (95% CI) n = 81 (%) OR (95% CI)
  1. Unadjusted odds ratios (OR) with 95% confidence intervals (CI).

Gender
 Male30/52 (57.7)120/51 (38.5)1
 Female86/116 (74.1)2.1 (1.1–4.2)61/116 (52.6)1.8 (0.9–3.5)
Age
 75–79 years61/90 (67.8)147/90 (52.2)1
 ≥8055/78 (70.5)1.1 (0.6–2.2)34/88 (38.6)0.7 (0.4–1.3)
Education
 7 years or more65/92 (70.7)149/92 (53.3)1
 <7 years49/73 (67.1)0.8 (0.4–1.7)30/73 (41.1)0.6 (0.3–1.1)
Number of teeth
 ≥2044/60 (73.3)142/60 (70.0)1
 10–1931/42 (73.8)1.0 (0.4–2.5)19/42 (45.2)0.4 (0.2–0.8)
 <1041/66 (62.1)0.6 (0.3–1.3)20/66 (30.3)0.2 (0.1–0.4)
Has feeling of dry mouth
 No50/85 (58.8)132/85 (41.2)1
 Yes66/83 (79.5)2.8 (1.4–5.4)46/83 (55.4)1.8 (1.1–3.3)
Has own dentist
 No31/77 (62.3)127/77 (35.1)1
 Yes67/90 (74.4)1.8 (0.9–3.4)53/90 (58.9)2.7 (1.4–5.0)
MMSE score 0–30
 Low (≤26)29/57 (50.9)118/57 (31.6)1
 High (27–30)87/111 (78.4)3.5 (1.8–7.0)63/111 (56.8)2.8 (1.5–5.6)
IADL score 0–8
 Low (≤6)17/38 (44.7)110/38 (26.3)1
 High (7–8)98/129 (76.0)3.9 (1.8–8.3)71/129 (55.0)3.4 (1.5–7.6)
Handgrip strength
 Lowest tertile37/55 (67.3)125/55 (45.5)1
 Upper tertiles78/110 (70.9)1.2 (0.6–2.5)55/110 (50.0)1.2 (0.6–2.3)
Table 3.   Factors associated with good oral hygiene (plaque teeth 0–20%).
  Good oral hygiene
n = 56 (%) OR (95% CI)
Gender
 Male14/52 (26.9)1
 Female42/116 (36.2)1.5 (0.8–3.2)
Age
 75–7935/90 (38.9)1
 ≥8021/88 (26.9)0.6 (0.3–1.1)
Education
 7 years or more32/92 (34.8)1
 <7 years23/73 (31.5)0.9 (0.5–1.7)
Number of teeth
 ≥2023/60 (38.3)1
 10–919/42 (45.2)1.3 (0.6–3.0)
 <1014/66 (21.2)0.4 (0.2–1.0)
Has feeling of dry mouth
 No29/85 (34.1)1
 Yes27/83 (32.5)0.9 (0.5–1.8)
Has own dentist
 No24/77 (31.2)1
 Yes31/90 (34.4)1.2 (0.6–2.2)
Toothbrushing
 At least twice a day44/116 (37.9)1
 <Twice a day12/52 (23.1)0.5 (0.2–1.0)
Toothpaste
 At least twice a day32/81 (39.5)1
 <Twice a day14/87 (16.1)0.6 (0.3–1.1)
MMSE score 0–30
 Low (≤26)14/57 (24.6)1
 High (27–30)42/111 (37.8)1.9 (0.9–3.8)
IADL score 0–8
 Low (≤6)6/38 (15.8)1
 High (7–8)50/129 (38.8)3.4 (1.3–8.7)
Handgrip strength
 Lowest tertile16/55 (29.1)1
 Upper tertiles40/160 (36.4)1.4 (0.7–2.8)

Ethical issues

Written informed consent was obtained from the study participants or their relatives. The study protocol was approved by the Research Ethics Committee of the Hospital District of the Northern Savo as required by Finnish legislation.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

Among the study participants, 69% brushed their teeth at least twice a day (76% in the high IADL group and 45% in the low IADL group) (Table 1). Forty-eight per cent of the participants used toothpaste twice a day (55% in the high IADL group and 26% in the low IADL group). Thirty-three per cent of the participants had 0–20% teeth with dental plaque and were considered to have good oral hygiene (38.8% in the high IADL group and 15.8% in the low IADL group). In the lowest hand grip strength tertile, 29.1% of the subjects had good oral hygiene compared to 36.4% of participants in the upper hand grip strength tertiles.

Unadjusted odds ratios for explanatory variables are shown in Tables 2 and 3. After controlling for confounding factors such as gender, age, education, number of teeth, having a feeling of dry mouth, having own dentist and cognitive status (MMSE), there was an association between high IADL scores and toothbrushing frequency, toothpaste use and good oral hygiene. The participants with an IADL score of 7–8 were more likely to brush their teeth twice a day OR 2.7 (95% CI 1.1–6.8), to use toothpaste twice a day OR 2.0 (95% CI 0.8–5.2) and to have good oral hygiene OR 2.8 (95% CI 1.0–8.3), than those participants with IADL scores less than 7 (Table 4).

Table 4.   Associations between toothbrushing, toothpaste use and good oral hygiene and IADL and the handgrip strength.
  Toothbrushing at least twice a day OR a (95% CI) Toothpaste use at least twice a day OR a (95% CI) Good oral hygiene OR a (95% CI)
  1. Results of multivariate logistic regression analyses, adjusted odds ratios (OR) with 95% confidence intervals (CI).

  2. aAdjusted for gender, age as continuous, education as continuous, number of teeth, having feeling of dry mouth, having own dentist and MMSE score.

IADL score 0–8
 Low (≤6)111
 High (7–8)2.7 (1.1–6.8)2.0(0.8–5.2)2.8 (1.0–8.3)
Handgrip strength
 Lowest tertile111
 Upper tertiles0.9 (0.4–1.9)0.9 (0.4–1.8)1.1 (0.5–2.4)

The adjusted ORs for the participants in the upper tertiles of the hand grip strength for toothbrushing at least twice a day were 0.9 (95% CI 0.4–1.9), for toothpaste use at least twice a day 0.9 (95% CI 0.4–1.8) and for good oral hygiene 1.1 (95% CI 0.5–2.4), as compared to the study subjects in the lowest handgrip strength tertile (Table 4).

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

In this study population, one out of four people had at least two restrictions in performing IADL activities. Our results showed that those people with IADL scores 0–6 were less likely to brush teeth twice a day, less likely to use toothpaste and less likely to have good oral hygiene than person with zero or only one deficiency in IADL activities. In contrast to functional status, handgrip strength had only a weak and statistically non-significant association with toothbrushing frequency, toothpaste use and oral hygiene.

It has been previously demonstrated that most people have difficulty maintaining an effective level of plaque control13. Improving the ability of a person to perform supragingival plaque removal is not easy22. However, maintaining good oral hygiene has been shown to be important; for example in a 30-year prospective study14 it was observed that >80% plaque free surfaces corresponded with long-term periodontal health and stability. In the present study, only one-third of the participants had succeeded in plaque removal. Compared to the results of previous studies, the proportion of participants who succeeded in plaque removal was low. For example, Axelsson et al.14 and van der Wiejden13 reported that among younger persons, the plaque removal success rate was 50–60% on all teeth surfaces, and that 40–55% of plaque was commonly removed. On the other hand, it has been reported that the mean proportion of teeth with plaque increased from 30% in the 25–34 year age group and to 44% in those aged 65 or above23.

The efficacy of toothbrushing on plaque removal is dictated by three main factors, other than the level of motivation of the person: the design of the brush, the skill of the individual using the brush and frequency and duration of use13,22. The results of this study emphasise that the inability to perform daily activities (low IADL scores), but not the hand grip strength is associated with poor oral self-care. The lack of association between oral self-care and handgrip strength may be explained by the fact that among this population, the reserve capacity of handgrip strength and the safety margin may still exist, preventing the development of disability related to physical strength7,24. It means that even though strength has decreased by age, it is possible that among home-dwelling subjects handgrip strength has not yet reached the threshold for disability for oral self-care.

Strengths and limitations

An important strength of this study was the population-based sampling strategy. Another strength was that two trained study nurses performed the IADL tests, two trained physiotherapists the handgrip strength and two dentists performed the clinical oral examinations. One limitation, however, was that repeated oral examinations were not performed. This meant that the intra- and inter-examiner reliability of clinical oral examinations could not be assessed.

The participation rate in the oral health component of the study was 70.8%. When only home-dwellers were included the participation percentage was 64.2. The main reasons cited for non-participation in the study were frail general health, having no teeth, and no need for an oral examination’. The participation rate was maximised by offering dental home visits. This is despite the fact it is more challenging to perform a clinical oral examination in a person’s home than in the dental clinic. The non-participants were not closely examined. However, given that frail general health was reported as a reason for non-participation, it is reasonable to believe that many of the non-participants had a high degree of functional limitation.

The distribution of IADL scale scores in this study population corresponded well to those reported in earlier studies25,26. The categorisation of IADL scores, which was based on the mean value, seemed, despite its robustness, to identify fairly well those elderly people at risk of inadequate oral self-care or poor oral hygiene.

The age- and gender-specific mean values of the hand grip strength concurred with the results of old community-dwelling population reported earlier8,27,28. It is therefore not likely that the absence of any significant association with oral self-care and poor hygiene would be a result of exceptional high handgrip strength in this population. However, it must be admitted that a lack of essential associations between hand grip strength and oral self-care and oral hygiene may partly be due to categorisation (lowest tertile vs. middle and highest tertiles) of hand grip strength variable. Our findings therefore does not totally exclude the possibility that there might be few individuals having exceptionally low grip strength, which actually prevent them performing daily oral self-care.

One of the most important confounding factors in this context is cognitive function due to the close association with cognitive function and IADL29. In order to reduce this effect we adjusted also for cognitive function (measured by MMSE). In this adjustment we used the cut-point 26, which was based on the mean value of MMSE among our study subjects. The MMSE value 26 has been used also as a discriminatory value when screening cognitive deficiencies30.

Implications for clinicians

General dental practice for elderly people is predominantly focused on somatic diseases and medication. However, our results highlight the importance for dentists to identify patients who may be unable to perform the instrumental activities of daily living and, therefore, may require assistance to maintain adequate oral self-care. Our results suggest that elderly people, especially those with impaired functional ability, may have difficulties in plaque removal. To promote oral cleanliness powered toothbrushes could benefit elderly people with and without functional impairment because it has been found that powered toothbrushes reduce plaque and gingivitis significantly better than manual toothbrushes31–33. In addition, patients with xerostomia problems, which are common among elderly people, may benefit from using powered toothbrushes34.

Conclusions

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

In conclusion, this study suggests that home-dwelling elderly people who are unable to perform the activities of daily living are at risk for inadequate oral self-care. IADL scores, but not the handgrip strength, appear to be an important determinant of oral self-care among the home-dwelling elderly.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References

The GeMS-study was financially supported by the Social Insurance Institute of Finland and the city of Kuopio. Kaija Komulainen wishes to thank for The Finnish Dental Society for financial support, Piia Lavikainen for statistical guidance and J. Simon Bell for revision of the English text.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Conclusions
  8. Acknowledgements
  9. References