Environmental and Geographic Patterns of Occupational Injuries (WEATHER-WORK)

Environmental and Geographic Patterns of Occupational Injuries: A Population-Based Retrospective Study

This study will determine whether extreme ambient temperatures increase the incidence and severity of occupational injuries in Israel, and we request Helsinki Committee approval to conduct the analysis using de-identified National Insurance and historical meteorological data, with a waiver of informed consent. The project will link the date, time, and geographic location of recognized occupational accidents with corresponding historical temperature and humidity measurements. The study is retrospective, observational, and involves no direct contact with participants, no intervention, and no alteration of medical care or benefit eligibility.

Study Overview

• Status: Active, not recruiting
• Conditions: Occupational Accidents; Weather
• Intervention / Treatment: Other: Ambient Weather Exposure

Detailed Description

Occupational injuries represent an important source of preventable morbidity, permanent disability, loss of employment, and economic burden. Rising temperatures and increasingly frequent heatwaves may impair concentration, coordination, judgment, reaction time, hydration, and physical endurance, particularly among workers in construction, agriculture, transportation, manufacturing, and other outdoor or physically demanding occupations. However, the national relationship between ambient heat and work-related injury in Israel has not been adequately quantified. Without reliable population-level evidence, employers, occupational-health authorities, and policymakers cannot identify temperature thresholds at which preventive measures should be intensified or determine which workers and industries are at greatest risk.

• Study Type: Observational
• Enrollment (Actual): 350000

Contacts and Locations

Study Locations

• Israel
  • Rishon LeZiyyon, Israel, 7526557
    • Israel National Insurance Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

The study population will include adults aged 18 years or older with occupational injuries recognized by the National Insurance Institute between January 1, 2020, and December 31, 2024. Eligible records will be selected from the national occupational-injury administrative database and assigned to one of seven predefined geographic-climatic regions according to the workplace or accident location. Environmental exposure will be determined by linking each injury date, time, and location to the nearest representative meteorological monitoring station. The study will include workplace, occupational-traffic, and commuting injuries meeting the prespecified eligibility criteria.

Description

Inclusion Criteria:

• Individuals aged 18 years or older with an occupational injury recognized by the National Insurance Institute.
• Occupational injury occurring between January 1, 2020, and December 31, 2024.
• Injury occurring at the workplace, during occupational travel, or while commuting to or from work.
• Valid injury date and geographic information sufficient to assign the accident to one of the seven predefined geographic-climatic regions and the nearest representative meteorological station.
• Meteorological measurements available for the injury period and eligible matched control periods.

For time-specific analyses, a valid recorded accident time permitting linkage to the closest preceding three-hour meteorological observation.

Exclusion Criteria:

• Occupational diseases, repetitive-exposure conditions, or gradual-onset disorders without a clearly defined accident date.
• Rejected, withdrawn, or unconfirmed occupational-injury claims.
• Missing or invalid accident date or geographic information preventing linkage with meteorological data.
• Accidents occurring outside the predefined geographic-climatic regions or beyond the prespecified maximum distance from an eligible meteorological station.
• Duplicate or administratively repeated records referring to the same occupational-injury event.
• Injury events for which no eligible matched control periods or corresponding meteorological measurements are available.
• Individuals younger than 18 years.

Study Plan

How is the study designed?

Number of groups / cohorts

7

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Northern valleys and inland north; Occupational injuries occurring in the northern valleys and inland northern region will be assigned to this geographic-climatic division according to the location of the workplace or accident. Meteorological exposure will be determined using data from the nearest representative monitoring station, including Dafna, Tavor Kadoorie, or Nazareth. This region is characterized by inland climatic conditions with substantial seasonal variation in temperature and humidity. Accident occurrence and severity will be evaluated in relation to temperature, relative humidity, wind speed, extreme heat, extreme cold, and other predefined environmental indicators.	Other: Ambient Weather Exposure; Ambient temperature, relative humidity, and wind speed at the occupational-injury location and time will be retrospectively obtained from the nearest representative meteorological monitoring station. Environmental exposures will be analyzed in relation to occupational-injury occurrence and severity.
Northern Mediterranean coast; Occupational injuries occurring along the northern Mediterranean coastal region will be assigned to this geographic-climatic division according to the location of the workplace or accident. Meteorological exposure will be determined using data from the Haifa Technion monitoring station or the nearest available representative station. This region is characterized by a Mediterranean coastal climate, with relatively high humidity, moderate winter temperatures, warm summers, and frequent sea-breeze effects. Accident occurrence and severity will be evaluated in relation to ambient temperature, relative humidity, wind speed, extreme heat, extreme cold, and other predefined environmental indicators.	Other: Ambient Weather Exposure; Ambient temperature, relative humidity, and wind speed at the occupational-injury location and time will be retrospectively obtained from the nearest representative meteorological monitoring station. Environmental exposures will be analyzed in relation to occupational-injury occurrence and severity.
Central Mediterranean coast; Occupational injuries occurring within the central Mediterranean coastal region will be assigned to this geographic-climatic division according to the workplace or accident location. Meteorological exposure will be determined using data from the Tel Aviv Coast monitoring station or the nearest available representative station. This region is characterized by a warm Mediterranean climate, relatively high humidity, mild winters, hot summers, and frequent sea-breeze effects. The occurrence and severity of occupational injuries will be evaluated in relation to ambient temperature, relative humidity, wind speed, extreme heat, extreme cold, and other predefined environmental indicators.	Other: Ambient Weather Exposure; Ambient temperature, relative humidity, and wind speed at the occupational-injury location and time will be retrospectively obtained from the nearest representative meteorological monitoring station. Environmental exposures will be analyzed in relation to occupational-injury occurrence and severity.
Southern Mediterranean coast; Occupational injuries occurring within the southern Mediterranean coastal region will be assigned to this geographic-climatic division according to the workplace or accident location. Meteorological exposure will be determined using data from the Ashqelon Port monitoring station or the nearest available representative station. This region is characterized by a warm coastal Mediterranean climate, relatively high humidity, mild winters, hot summers, and frequent sea-breeze effects. The occurrence and severity of occupational injuries will be evaluated in relation to ambient temperature, relative humidity, wind speed, extreme heat, extreme cold, and other predefined environmental indicators.	Other: Ambient Weather Exposure; Ambient temperature, relative humidity, and wind speed at the occupational-injury location and time will be retrospectively obtained from the nearest representative meteorological monitoring station. Environmental exposures will be analyzed in relation to occupational-injury occurrence and severity.
Central highlands; Occupational injuries occurring within the central highlands region will be assigned to this geographic-climatic division according to the workplace or accident location. Meteorological exposure will be determined using data from the Jerusalem Centre monitoring station or the nearest available representative station. This region is characterized by higher elevation, lower average humidity than the coastal areas, greater day-night temperature variation, cooler winters, and warm, dry summers. The occurrence and severity of occupational injuries will be evaluated in relation to ambient temperature, relative humidity, wind speed, extreme heat, extreme cold, and other predefined environmental indicators.	Other: Ambient Weather Exposure; Ambient temperature, relative humidity, and wind speed at the occupational-injury location and time will be retrospectively obtained from the nearest representative meteorological monitoring station. Environmental exposures will be analyzed in relation to occupational-injury occurrence and severity.
Negev desert; Occupational injuries occurring within the Negev desert region will be assigned to this geographic-climatic division according to the workplace or accident location. Meteorological exposure will be determined using data from the Avdat monitoring station or the nearest available representative station. This region is characterized by an arid desert climate, very low relative humidity, intense solar exposure, high daytime temperatures, substantial day-night temperature variation, and limited rainfall. The occurrence and severity of occupational injuries will be evaluated in relation to ambient temperature, relative humidity, wind speed, extreme heat, extreme cold, and other predefined environmental indicators.	Other: Ambient Weather Exposure; Ambient temperature, relative humidity, and wind speed at the occupational-injury location and time will be retrospectively obtained from the nearest representative meteorological monitoring station. Environmental exposures will be analyzed in relation to occupational-injury occurrence and severity.
Dead Sea and extreme arid region; Occupational injuries occurring within the Dead Sea and extreme arid region will be assigned to this geographic-climatic division according to the workplace or accident location. Meteorological exposure will be determined using data from the Massada monitoring station or the nearest available representative station. This region is characterized by very low elevation, an extremely hot and arid climate, low annual rainfall, intense solar radiation, prolonged periods of extreme heat, and substantial seasonal temperature variation. The occurrence and severity of occupational injuries will be evaluated in relation to ambient temperature, relative humidity, extreme heat, extreme cold, and other predefined environmental indicators. Wind speed will be analyzed when reliable measurements are available.	Other: Ambient Weather Exposure; Ambient temperature, relative humidity, and wind speed at the occupational-injury location and time will be retrospectively obtained from the nearest representative meteorological monitoring station. Environmental exposures will be analyzed in relation to occupational-injury occurrence and severity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occurrence of Recognized Occupational Injury During Case Versus Matched Control Periods	The number of accepted occupational-injury events occurring during predefined case periods will be evaluated in relation to ambient temperature, relative humidity, and wind speed obtained from the nearest representative meteorological station. Each injury period will be compared with control periods matched by geographic-climatic region, calendar year and month, day of the week, and three-hour time interval. The association between environmental exposure and occupational-injury occurrence will be estimated using time-stratified case-crossover analysis with conditional logistic regression.	At the index injury date and matched control dates, January 1, 2020-December 31, 2024.

Collaborators and Investigators

• Sponsor: Sergio Gabriel Susmallian
• Investigators: Study Director: Eytan Ellenberg, M.D., Israel National Insurance Institute

Publications and helpful links

General Publications

• Calkins MM, Bonauto D, Hajat A, Lieblich M, Seixas N, Sheppard L, Spector JT. A case-crossover study of heat exposure and injury risk among outdoor construction workers in Washington State. Scand J Work Environ Health. 2019 Nov 1;45(6):588-599. doi: 10.5271/sjweh.3814. Epub 2019 Mar 14.
• Sheng R, Li C, Wang Q, Yang L, Bao J, Wang K, Ma R, Gao C, Lin S, Zhang Y, Bi P, Fu C, Huang C. Does hot weather affect work-related injury? A case-crossover study in Guangzhou, China. Int J Hyg Environ Health. 2018 Apr;221(3):423-428. doi: 10.1016/j.ijheh.2018.01.005. Epub 2018 Jan 11.
• Marinaccio A, Scortichini M, Gariazzo C, Leva A, Bonafede M, De' Donato FK, Stafoggia M, Viegi G, Michelozzi P; BEEP Collaborative Group. Nationwide epidemiological study for estimating the effect of extreme outdoor temperature on occupational injuries in Italy. Environ Int. 2019 Dec;133(Pt A):105176. doi: 10.1016/j.envint.2019.105176. Epub 2019 Oct 22.

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2020
• Primary Completion (Actual): December 31, 2024
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: August 2, 2026
• First Submitted That Met QC Criteria: August 2, 2026
• First Posted (Actual): August 6, 2026

Study Record Updates

• Last Update Posted (Actual): August 7, 2026
• Last Update Submitted That Met QC Criteria: August 6, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: BTL 001-2026; work accidents and weather (Other Identifier: Israel National Insurance Institute)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be publicly shared because the study uses confidential administrative records owned and controlled by the National Insurance Institute. Access is restricted to authorized researchers within a secure research environment and is governed by institutional confidentiality agreements, data-protection requirements, and applicable privacy legislation. The combination of accident dates, geographic information, occupational characteristics, and disability outcomes may create a residual risk of participant re-identification even after removal of direct identifiers. Only aggregated, disclosure-controlled results approved by the data custodian may be reported or published.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No