The new services consisted of the following that were specifically designed to bring functional improvement: physical strength training, and guidance for nutrition and oral function. These services are provided on an individual basis, and not for a group, as is the case for eligibility levels 3 to 7. In addition, the responsibility for care planning and care management for those in the two lightest of the seven eligibility levels has been transferred from agencies selected by the users to Local Comprehensive Support Centres operated or supervised by municipalities [7, 8].

The preventive care programme was initiated by the report to the Ministry of Health, Labour and Welfare (henceforth "Ministry") about rehabilitation for elders which stated that "there should be a shift from a 'stroke-based model' to a 'disuse syndrome model' [9]. As an example of 'disuse syndrome', it stated that "despite having the ability to cook and perform other household chores, the use of home help services has led to a gradual decline in ability." The Ministry's Preventive Care Management Manual states that "when selecting services for the two lightest eligibility levels, day care should be actively promoted. By doing so, daily activities and opportunities for social contact would be enhanced so that the disuse syndrome could be prevented or improved. Home help services should be limited to tasks that are difficult to perform independently (cleaning, shopping, cooking etc.), and whether these services are to be provided or not should be considered based on the number of the family members who are living together in the same household, and when community mutual support and other welfare services are not available [8]." Based on the assumption that the preventive care programme would succeed, the Ministry instructed local governments to draw their municipal LTCI plan so that "the percentage of those declining in function from the three lightest eligibility levels to the fourth eligibility level would be reduced by 10% [10]."

The Ministry has not offered sufficient evidence to support this new policy initiative. Although a cohort analysis by the Ministry of 5,000 people eligible for services before and after the LTCI revisions showed a decrease in the rate of who had progressed to heavier eligibility levels after the revisions [11], this study did not consider the length of the observation time before the decline took place, nor was the relationship with service utilization reported. When we reviewed earlier studies that examined the relationship between the use of home help services and functional status, we found none that reported its use led to a decline in function [5, 12–14]. We conclude that the validity of the new policy to contain the use of home help services and encourage the use of day care services has not been adequately demonstrated among those using these services.

This study focused on the validity of the government policy to contain home help services and encourage day care services. We limited our subjects to those who had actually started using services after the implementation of the reform and to those in the lightest eligibility Level 1. Even though they were in the lightest level, over half were 80 and over. This could be the main reason why 27.8% had declined one and a half year later. The proportion of decline from IADL disability only to ADL disability was about 10 to 15% among those 75 and over [20–24].

Similar to previous studies, we found that people who had no primary caregiver, or whose primary caregiver came from outside the household, were more likely to choose home help, while those whose primary caregiver lived in the same household were more likely to go to day care [25, 26]. However, even after controlling for these variables, home help service users were found to have a lower risk of functional decline than day care service users. And providing more home help services did not lead to greater decline in function. These findings contradict the assumptions of the Ministry's policy.

Before concluding that those assumptions are wrong, we should consider alternative explanations. First, could the day care users have been more frail than the home help users at the start? Although we have statistically controlled for age, there could be other factors such albumin to total protein level [27–29], and subjective measurement of health [30–32], which could have had implications on the subjects' intrinsic frailty. However, in the research design, subjects were limited to those of the lightest eligibility level, and the outcome required them to decline by three levels to Level 4. Therefore, any slight differences appearing at baseline or during the observation period were unlikely to be reflected in the results. Note also that only new users with no history of LTCI service use were included, and that since data was limited to usage claims within three months from initial eligibility certification, the possibility of a reverse cause-effect relationship (decline leading to the start of service) would be low.

Second, could the day care services that the subjects received be less focused on preventive care services than the norm? The Ministry's model programme, which added selective muscle strength training and improvement of nutrition and oral function on top of their former services, was reported to have been effective [33]. In theory, it would have been possible to widely replicate and disseminate this model. A systematic review of day care programmes revealed that sites that had comprehensive preventive care interventions achieved some success. However, in this review, only a few sites showed success [34] and whether these results could be generalized remains doubtful.

In Japan, although Kuzaya et al have reported that the use of day care services had a positive effect on lowering the mortality rate, both the intervention and the subjects differed from our study [35]. Kuzuya et al conducted their research prior to the implementation of the preventive services and their subjects spanned across all eligibility levels, among which two-thirds had ADL disability. An analysis of 20,000 day care service users in Tokyo conducted after the implementation showed that there were no differences in the functional decline as measured by eligibility levels between those who had selected muscle strength training and improvement of nutrition and oral function, and those who had not. Most day care services appeared to be still focussed on recreation and bathing services, and providing respite care to caregivers who live in the same household [36]. Thus, the fact that those receiving day care services in our study did not improve was not surprising.

Third, did providing excessive home help services lead to a greater proportion of the users to decline as the Ministry has claimed? Our analysis of time-dependent variables after controlling for the presence of caregiver and other factors showed no particular change in the risk of decline in functional status for those who used more than two hours of home help services per week compared to those who used less. This is not surprising. Looking at the substance of the programme, it is implausible that the provision of only one or two hours of home help services per week would lead to disuse syndrome.

Our study was limited to those who had been assessed to be in Level 1, and to those who had been using home help services or day care services, as this was focus of the new reform policy. Whether either service would have any effect compared to non-users remains to be explored, or for that matter, compared to those who have a similar level of disability, but who have not yet been assessed. Further research is needed. Our study was also confined to a single area which had a higher rate of home help service use and somewhat lower day care service use compared to the national average (Table 2). This is similar to other urban municipalities that tend to have relatively well-established home help service provision. Further studies should be made in rural municipalities that have the opposite traits.

In the new preventive care policy for those requiring light care, the Ministry claimed money could be saved by encouraging day care services, and containing home help services. However, our study showed contrary results: home help service users were found to have a lower risk of functional decline than day care service users.