I. INTRODUCTION

From 2007 to 2019, every August in Yakumo Town, Hokkaido, the authors examined the sense of taste and olfactory tests during a health checkup for residents ${}^{1-12}$.

However, in 2020 and 2021, we could not undergo a medical examination due to the COVID-19 epidemic.

As the COVID-19 epidemic has subsided, this fiscal year (August 2022), Hokkaido, August.

We obtained the taste and smell test results during the health checkup for the residents of Yakumo Town.

Therefore, we compared the taste and smell test results obtained in 2019 and the taste and smell test results obtained in 2022.

I decided to confirm whether or not there was an impact of COVID-19 by comparing two data.

II. MATERIAL AND METHOD

Among the participants in the health checkup for Yakumo town residents were measured for height, weight, blood pressure (systolic and diastolic), salty taste tests, and olfactory tests.

There were 298 subjects (129 males 169 females) in 2019.

And there were 344 subjects (142 males, 202 females) in 2022.

Survey items comparing 2019 and 2022 are age, height, weight, systolic blood pressure, diastolic blood pressure, the results of a simple olfactory test, and the results of a simple salty taste test.

The results of the simple salty taste test were performed by using Salsive (manufactured by Advantech). The Salsive is the filter paper. Salsive comes in 6 different salt concentrations (0.6% 0.8%, 1.0% 1.2%, 1.4%, 1.6%). Participants put Salsive in their mouth to check the salty taste.

Concentration was recorded when participants perceived salty testosterone¹³⁾.

The results of the simple olfactory test were performed using an odor stick (Daiichi Yakuhin Kogyo Co., Ltd.).

Twelve kinds of odors are applied to the filter paper (Japanese ink, wood, perfume, menthol, mandarin orange, curry, household gas, roses, cypress, stuffy socks/sweaty, condensed milk, fried garlic). The number of odors perceived by participants was recorded.

The obtained data were statistically processed by sex and age groups.

Whitney test was performed to confirm the presence or absence of statistical significance.

a) Ethical review board

This study conducted with the approval of the Ethical Review Board (Nagoya women's University Ethics Committee: "hitowomochiitakennkyuuni-kannsuruiinnkai"). The approval number is 2019-26.

III. RESULT

There were 298 participants (129 male and 169 female) in 2019, and 344 participants (142 male and

2022 female) in 2022. The distribution of each age group is shown in Table 1. In both years, there were many participants in their 60s and 70s.

Table 2 shows the average values and standard deviations by age group for each inspection item in FY2019.

The average systolic blood pressure for both males and females in their 70s and 80s was $140\mathrm{mmHg}$, exceeding the normal range.

However, the average diastolic blood pressure was $90\mathrm{mmHg}$ or less in both men and women, which was within the normal range.

The average value of the simple olfactory test results in the 80s female was six, and half of the twelve types of odors could be recognized. All females of other ages had a simple olfactory test result of six or higher.

However, the average value for males was six or less, resulting in a less recognizable odor.

The average value of salty taste test results for women in their 80s exceeds hers by $1.0\mathrm{\%}$.

But otherwise, both males and females, in the age-specific salty taste test results, salty taste could be recognized less than $1.0\mathrm{\%}$.

Table 3 shows the average values and standard deviations by age group for each inspection item in FY2022.

In females, the average systolic blood pressure in their 70s and 80s is over $140\mathrm{mmHg}$, which exceeds the normal range.

And also in males, the average systolic blood pressure in their 80s is over $140\mathrm{mmHg}$, which exceeds the normal range.

However, the mean diastolic blood pressure for both males and females was below $90\mathrm{mmHg}$, which was within the normal range.

Females in their 80's and males in their 80's and 70's recognized six or less of the twelve odors. As a result, olfactory recognition decreased with age.

The results of the salty taste test showed that they could recognize less than $1.0\mathrm{\%}$ salty taste for both males and females.

The results of 2022 and 2019 were compared using statistical methods.

The results of comparing the age distribution of females in 2022 and 2019 showed Table 4. As a result, there was no statistically significant difference between 2022 and 2019.

Table 4 Age Comparison Results for 2019 and 2022 Participants Female (169 in 2019, 202 in 2022)

The results of comparing the age distribution of males in 2022 and 2019 showed Table 5. As a result, there was no statistically significant difference between 2022 and 2019.

Table 5 Age Comparison Results for 2019 and 2022 Participants Male (129 in 2019, 142 in 2022)

The results of comparing the height distribution of females in 2022 and 2019 showed Table 6. As a result, there was no statistically significant difference between 2022 and 2019.

Table 6 Hight Comparison Results for 2019 and 2022 Participants Female (169 in 2019, 202 in 2022)

The results of comparing the height distribution of males in 2022 and 2019 showed Table 7. As a result, there was no statistically significant difference between 2022 and 2019.

Table 7 Hight Comparison Results for 2019 and 2022 Participants Male (129 in 2019, 142 in 2022)

The results of comparing the weight distribution of females in 2022 and 2019 showed Table 8. As a result, there was no statistically significant difference between 2022 and 2019.

Table 8 Weight Comparison Results for 2019 and 2022 Participants Female (169 in 2019, 202 in 2022)

The results of comparing the weight distribution of males in 2022 and 2019 showed Table 9. As a result, there was no statistically significant difference between 2022 and 2019.

Table 9 Weight Comparison Results for 2019 and 2022 Participants Male (129 in 2019, 142 in 2022)

The results of comparing the systolic blood pressure distribution of females in 2022 and 2019 showed Table 10. As a result, there was no statistically significant difference between 2022 and 2019.

Table 10 Systolic Blood Presure Comparison Results for 2019 and 2022 Participants Female (169 in 2019, 202 in 2022)

The results of comparing the systolic blood pressure distribution of males in 2022 and 2019 showed Table 11. As a result, there was no statistically significant difference between 2022 and 2019.

Table 11 Systolic Blood Presure Comparison Results for 2019 and 2022 Participants Male (129 in 2019, 142 in 2022)

The results of comparing the diastolic blood pressure distribution of females in 2022 and 2019 showed Table 12. As a result, there was no statistically significant difference between 2022 and 2019.

Table 12 Diastolic Blood Pressure Comparison Results for 2019 and 2022 Participants Female (169 in 2019, 202 in 2022)

Table 13 shows the results of comparing males' systolic blood pressure by age group.

Although there was no statistically significant difference by age group, ( $\mathrm{P}={0.045}^{\star }$ ) for all age groups.

The results showed that the diastolic blood pressure in 2022 was statistically significantly lower than the diastolic blood pressure in 2019.

Table 13 Diastolic Blood Pressure Comparison Results for 2019 and 2022 Participants Male (129 in 2019, 142 in 2022)

Table 14 shows the results of a comparison of females' olfactory test results by age group.

A statistically significant difference comes out in their seventies. In 2022, olfactory recognition was statistically significantly lower than in 2019 (P<0.05: P=0.024*). Comparing the results of the olfactory cognition test in 2022 and 2019, there was no statistically significant difference in each age group. However, as a result of the overall comparison, olfactory recognition was statistically significantly lower in 2022 than in 2019.

表14 Olfactory test results Comparison Results for 2019 and 2022 Participants Female (169 in 2019, 202 in 2022)

Table 15 shows the results of a comparison of male olfactory test results by age group.

A statistically significant difference comes out when he is in the 40s. In 2022, olfactory recognition was statistically significantly lower than in 2019 ( : $P={0.014}^{\star }$ ).

Comparing the results of the olfactory cognition test in 2022 and 2019, other were no statistically significant difference in each age group. However, as a result of the overall comparison, olfactory recognition was statistically significantly lower : $P={0.005}^{\ast \ast })$ in 2022 than in 2019.

Table 15 Olfactory test results Comparison Results for 2019 and 2022 Participants Male (129 in 2019, 142 in 2022)

Table 16 shows the results of comparing females' salt taste tests by age group. Comparing the results of the salt taste cognition test in 2022 and 2019, other were no statistically significant difference in each age group.

Table 16 Salty taste test results Comparison Results for 2019 and 2022 Participants Female (169 in 2019, 202 in 2022)

Table 17 shows the results of comparing males' salt taste tests by age group. Comparing the results of the salt taste cognition test in 2022 and 2019, other were no statistically significant difference in each age group.

Table 17 Salty taste test results Comparison Results for 2019 and 2022 Participants Male (129 in 2019, 142 in 2022)

IV. DISCUSSION

For both male and female participants, age, height, and weight were not statistically significantly differences for comparison between 2019 and 2022. Females had no statistically significant difference in blood pressure between 2019 and 2022. However, there was no significant difference in diastolic blood pressure among males by age group, but when compared overall, the year 2022 was lower than in 2019. There was no statistically significant difference in cognition between 2019 and 2022 for salty taste. Regarding the sense of smell, there will be a statistically significant decline in cognition in 2022 compared to 2019.

Whether this is due to the COVID-19 epidemic cannot be determined based on the results of this test alone. However, the results of this olfactory cognition test showed that the olfactory cognition in 2022 was lower than the olfactory cognition in 2019.

Therefore, we believe that it is necessary to continue to investigate the participants' sense of smell. At that time, we think it is needed to investigate COVID-19 morbidity as well. We believe it is necessary to track individuals individually.

Previous studies have reported a positive correlation between salt intake and blood pressure ${}^{15-19}$.

Therefore, in Japan and overseas, guidance to reduce salt intake is being carried out. Future studies will investigate the relationship dietary habits and blood pressure. It is necessary to investigate this in more detail. Relations with aging ${}^{20}$ and Alzheimer's disease ${}^{21,22}$ have also been reported regarding the decline in olfactory cognition. We could like to continue research on regional differences in Japan and clarify the results.

V. CONCLUSION

We compared taste and smelled simple test results before COVID-19 (2019) and after COVID-19 (2022). As a result, no statistically significant difference was observed in preference in all ages between 2019 and 2022. However, 2022 tended to have fewerol factory perceptions in all ages than in 2019. But the smell was a statistically significant difference between 2019 and 2019 in the total participants. Compared to 2022, the value tends to be lower in 2022, with a significant difference overall, and 2022 is not recognizable. It was found that the number of certain odors decreased in 2022. However, on this data, it cannot be concluded that the decline in olfactory recognition in 2022 was due to COVID-19.

In the future, we would like to clarify the presence or absence of regional differences by conducting surveys on more items and comparing them.

ACKNOWLEDGMENTS

This research was partially supported by the research aid of Choju-iryo-kenkyu-kaihatsuhi, 2022 (30-14, Hirokazu Suzuki) and Japanese Society of Taste Technology, 2021 (Naomi Katayam) and the Ministry of Education, Science, Sports and Culture, Grant-in Aid for Scientific Research(C), 2020-2022 (20K02372, Naomi Katayam). We would like to express my deepest gratitude here.