Evidence map›Paper›PMID 40511709›Full record

ArticleJournal of occupational health2025

Association between working hours, income, and work-related injury among freelancers in Japan: a cross-sectional study.

Kazuhiro Watanabe, Kazuhito Yokoyama, Akizumi Tsutsumi

Abstract read
In one paragraph

Article in Journal of occupational health, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors.

Kazuhiro WatanabeDepartment of Public Health, Kitasato University School of Medicine, 1-15-1 Kitazato, Minami-ku, Sagamihara 252-0374, Japan.ORCID 0000-0002-3342-6142
Kazuhito YokoyamaDepartment of Epidemiology and Social Medicine, Graduate School of Public Health, International University of Health and Welfare, 4-1-26 Akasaka, Minato-ku, Tokyo 107-8402, Japan.ORCID 0000-0003-3537-5657
Akizumi TsutsumiDepartment of Public Health, Kitasato University School of Medicine, 1-15-1 Kitazato, Minami-ku, Sagamihara 252-0374, Japan.ORCID 0000-0003-0966-4869

Funding

Ministry of Health, Labor, and Welfare, Japan
6 · The paper itself

Abstract

objectivesLimited empirical data are available regarding the safety of self-employed workers in Japan. This study investigated the associations between working hours, income, and work-related injuries among freelancers.

methodsA cross-sectional study was conducted using data from an internet survey conducted in 2022. Self-employed individuals who did not work as employees or earn an income from their employment were recruited. Work-related injuries, working hours, and annual income were assessed using self-reported questionnaires. Prevalence ratios (PRs) of injury were estimated using modified Poisson regression models, while controlling for covariates. Additionally, PRs were analyzed for each stratum of working hours and income levels.

resultsIn total, 1856 freelancers met the eligibility criteria and were included in the study. Among them, 222 (12.0%) experienced at least 1 work-related injury. A significantly higher risk of injury was observed among those working long hours (≥60 h/wk: PR = 1.65; 95% CI, 1.16-2.34; P = .005) and those in the second-lowest income bracket (¥2 to <¥4 million: PR = 1.43; 95% CI, 1.05-1.94; P = .024). Furthermore, several strata exhibited significantly higher PRs, particularly among workers with high incomes who also worked long hours (≥60 h/wk).

conclusionsLong working hours, particularly exceeding 60 h/wk, are associated with a significantly higher risk of work-related injuries among freelancers. Additionally, 2 high-risk groups were identified based on the combination of working hours and income levels: those with relatively low incomes, and high-income earners who also worked extended hours.

Indexed as

EmploymentIncomeOccupational InjuriesAdultCross-Sectional StudiesFemaleHumansJapanMaleMiddle AgedPrevalenceRisk FactorsSurveys and QuestionnairesYoung Adultoccupational healthprecarious employmentself-employmentwell-beingworkplace

Identifiers

PMID40511709
PMCPMC12229265

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.