Table 2.

The association between using the COVID-19 contact tracing application and sociodemographic factors and opinions among participants who owned a smartphone (n ​= ​1682).

	n	Odds ratioa (95% confidence interval)
Sociodemographic factor
Sex:
Men	811	Ref.f
Women	871	1.09 (0.80–1.49)
Age:
20–29 years	231	0.79 (0.46–1.37)
30–39 years	292	0.80 (0.49–1.32)
40–49 years	303	0.71 (0.44–1.17)
50–59 years	310	0.52 (0.32–0.85)∗
60–69 years	297	0.94 (0.60–1.46)
70–79 years	249	Ref.
Smoking:
Smokers	252	0.87 (0.60–1.25)
Non-smokers	1430	Ref.
Underlying diseasesb:
Yes	424	0.92 (0.67–1.26)
No	1258	Ref.
Marital status (married)
Married	1020	1.31 (0.92–1.87)
Not married	662	Ref.
Employment status:
Working	1118	1.46 (1.02–2.08)∗
Not working	564	Ref.
Residential area:
Metropolitan areac	1533	1.53 (0.94–2.49)
Nonmetropolitan area	149	Ref.
Living arrangement:
With others	1364	0.81 (0.55–1.21)
Alone	318	Ref.
Educational attainment:
University graduate level or above	912	1.04 (0.79–1.36)
Below University graduate level	770	Ref.
Annual personal income
<2 million yen [approximately 19,000 USD]	702	0.54 (0.34–0.87)∗
2-<4 million yen [19,000 -< 38,000]	430	0.55 (0.36–0.84)∗
4-<6 million yen [38,000 -< 57,000]	274	0.70 (0.46–1.06)
≥6 million yen [57,000-]	276	Ref.
Trust in theMinistry of Health, Labour and Welfare’s strategy for COVID-19d
Low	434	Ref.
Middle	613	1.07 (0.77–1.49)
High	635	1.14 (0.82–1.58)
Concerns about COVID-19 contact tracing application e
Insufficient knowledge of how to use the application
Yes	703	0.32 (0.24–0.44)∗
No	979	Ref.
Concerns about privacy
Yes	1056	0.40 (0.26–0.60)∗
No	626	Ref.
Security concerns
Yes	1097	0.86 (0.56–1.32)
No	585	Ref.
Doubt about the effectiveness of apps for preventing spread of infection
Yes	1275	0.52 (0.39–0.69)∗
No	407	Ref.
Would feel troubled if found to be in contact with an infected person
Yes	855	1.62 (1.22–2.14)∗
No	827	Ref.
Concerns about smartphone battery consumption and communication costs
Yes	829	0.61 (0.47–0.80)∗
No	853	Ref.

∗p-value: <0.05.

^aOdds ratios were calculated and adjusted for all individual variables.

^bUnderlying diseases included heart disease, respiratory disease, kidney disease, diabetes, and hypertension.

^cMetropolitan area included Tokyo, Kanagawa, Saitama, and Chiba prefecture.

^dParticipants responded using a 7-point scale to show the level of trust they had in the government’s strategy for COVID-19 (1 ​= ​very low trust, 7 ​= ​very high trust). When a participant responded with 1–3, 4, or 5–7 on the scale, level of trust in the Ministry of Health was defined as low, moderate, or high, respectively.

^eAnswers were assessed on a 4-point scale (1 ​= ​strongly disagree, 4 ​= ​strongly agree). A response of 3 or 4 was defined as “having concern” about that matter.

^fReference.