Serum a 1-Antichimotrypsin Levels and Cardiovasucular Risk Factors in the Japanese Elderly Population :

In recent years, an elevated serum a 1-antichimotrypsin (ACT) levels is associated with increased risk of Alzheimer-type dementia. The relationship between ACT and conventional various cardiovascular risk factors were studied using 589 noninstitutionalized individuals aged 65 and older living in the community in Japan. Serum ACT levels had no significantly differences between men and women, and had no significantly association with age in both sexes. Serum ACT levels had no statistically significant associated with body mass index, blood pressure, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol in both sexes. There were no significant differences in mean of serum ACT levels between in subjects with prevalent and subclinical cardiovascular disease and in those who were free of disease. A prospective study design is needed to clarify the relation between ACT and the development of Alzheimer-type dementia. J Epidemiol, 1998 ; 8 : 94-98.


Serum a 1-Antichimotrypsin Levels and Cardiovasucular Risk Factors in the Japanese
Elderly Population: Kazushi Okamoto1, Takashi Ito2, and Kiyoko Yagyu2 In recent years, an elevated serum a 1-antichimotrypsin (ACT) levels is associated with increased risk of Alzheimer-type dementia.The relationship between ACT and conventional various cardiovascular risk factors were studied using 589 noninstitutionalized individuals aged 65 and older living in the community in Japan.Serum ACT levels had no significantly differences between men and women, and had no significantly association with age in both sexes.Serum ACT levels had no statistically significant associated with body mass index, blood pressure, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol in both sexes.There were no significant differences in mean of serum ACT levels between in subjects with prevalent and subclinical cardiovascular disease and in those who were free of disease.
A prospective study design is needed to clarify the relation between ACT and the development of Alzheimer-type dementia.
J Epidemiol, 1998 ; and prevalent and subclinical cardiovascular disease.Serum ACT levels were no significant association with all categories of prevalent and subclinical cardiovascular disease.

DISCUSSION
We measured serum ACT levels in a population-based subjects of older living in a rural area in Japan.The subjects in this study were almost considered as a average elderly population, because there was no markedly differences in mean of TC level between in this subjects and in Japanese population in the age range considered17).
Because elevated serum levels of ACT have been shown to be an independent risk factor of ATD1.2.11.12)it is important to make its distribution clear and definite normal range for this concentration in healthy elderly subjects.We have observed that ACT values do not associated with any risk factor for atheroscleritic disease measured in the current cross-sectional   study.Almost all previous studies that have examined the relation between the serum ACT levels and cognitive impairment such as ATD have been based on subjects of demented individuals and controls or the residents in a home for the aged 2.11.12)Therefore , little data are available on normal range and distribution of ACT levels in a population-based sample of older living in the community.To our knowledge, this is the first study to determine the serum ACT levels in a populationbased subjects of older persons living in the community both in Japan and Western countries.
Although the sample size in this study is small, our result showing that the serum ACT levels were constant independent of sex and age is agreement with the results by others who investigated in Japan as ours 1,18) Most previous studies have reported no significant differences in serum ACT levels between men and women 1,18).
The mean serum ACT level in this study was almost similar to previous study in Japan 1.18.19) but was lower than in North American or in Europe 8.9).It is reported that prevalence of ATD is higher in North American or in Europe than that in Japan 20.21) So, it has been hypothesized that the regional differences in serum ACT levels may partially be explain the excess prevalence of ATD, although at present there are no data to support this speculation.It will be interesting to compare the differences in prevalence of ATD among countries and populations sampled with regional differences in ACT levels.
There is no report which is describe in the relationship between ACT levels and atherosclerotic risk factors.In this study, the serum ACT levels was no significant correlation with conventional atherosclerotic risk factors and prevalent and subclinical atheroscrelotic cardiovascular disease related to vascular dementia 1.11.12)Serum ACT levels were significantly higher in patient with ATD than in normal subjects and vascular dementia 1).Therefore, It was reported that there was no significant differences in serum ACT levels between normal subjects and vascular dementia 1).Matsubara et al. reported that the sensivity and specificity of ACT were satisfactory good 1.22).It has been reported that serum ACT levels has an association with cerebral amyloid.Antiserum to senile plaque cores recognized a protein that was produced from a liver complementary DNA(cDNA) library.Screening of cDNA revealed that the protein was ACT.Therefore, Anti-ACT serum recognized senile plaque in ATD brains 8.9).It was reported that serum ACT modified APOE*4 alle, which is a major risk factor of ATD 23).From these observations, a distinct elevation in serum ACT levels may reflect its upregurated condition in ATD.Accordingly, we suppose that measurement of serum ACT levels could be useful as a screening marker for ATD.
It is important to set cutoff value of serum ACT for screening of Alzheimer-type dementia in a population based.In previous studies, cutoff value of serum ACT vary from 25.2mg/dl 12) to 57.4mg/dl 13).although these differ by the methods of measurement.In this study, since the proportion of subjects with forgetfulness, which is well-known as subjective complaints related to Alzheimer-type dementia, was significantly at the ACT cutoff value of 40 mg/dl or higher, the risk range for ACT might be considered as 40 mg/dl or higher.Further research is needed to evaluate the risk attributable to ACT levels in this range (data is not shown).
There are several limitations that should be taken into account when interpreting our results.The design of our study is cross-sectional, and thus we are not able to ascertain to establish whether high serum ACT levels preceded or was the result of ATD.To our knowledge, no study has examined prospectively the relation between serum ACT levels and the development of ATD.A prospective study design is needed to clarify the relation between ACT and the development of AM In conclusion, the current study has revealed distribution of ACT in the elderly population.Serum ACT level was no agerelated changes and sex differences in this population.There was no statistically correlation of ACT with BMI, BP, TC, HDL, LDL, TG as risk of atheroscrelotic cardiovascular disease.Serum ACT levels had no statistically differences between in subjects with prevalent and subclinical atheroscrelotic cardiovascular disease and in those who were free of disease in both sexes.

Fig 1 .
Fig 1. Distribution of ACT levels by sex.
September 1996 in T-machi, a town adjoining of Nagoya in Aichi prefecture, Japan.All participants were able to walk without assistance of another person, and had no history of stoke and dementia confirmed by a 8 : 94-98.a 1 -anti chi motrypsi n, dementia, cardiovascular disease, elderly, Japan

Table 1 .
Number of subjects by age and sex and the response rate to the population.

Table 3 .
Pearson's correlation coefficients between ACT levels and risk factors for cardiovascular disease.

Table 5 .
Mean serum ACT levels for prevalent and subclinical diseases.

Table 4 .
Mean serum ACT levels by smoking history.