Cancer risk in information technology workers: a UK Biobank study

Abstract Background The information technology (IT) workforce has been growing more rapidly than others, with occupational health (OH) risks of sedentary behaviour, physical inactivity and poor diet, yet studies of their non-communicable disease risk, notably cancer, are lacking. Aims To investigate cancer risk in IT workers compared to others in employment and the nine major Standard Occupational Classification (SOC) groups. Methods We evaluated incident diagnosed cancers in the UK Biobank cohort through national cancer registry linkage. Cox proportional hazard regression models, with 15-year follow-up, were used to compare incident cancer risk among IT workers with all other employed participants and with the nine major SOC groups. Results Overall, 10 517 (4%) employed participants were IT workers. Adjusting for confounders, IT workers had a slightly lower cancer incidence compared to all other employed participants (Model 2: hazard ratio = 0.91, 95% confidence interval [CI] 0.83–1.01). Compared to the nine major SOC groups, they had a similar (Major Groups 2, 5 and 8) or lower (Major Groups 1, 3, 4, 6, 7 and 9) cancer incidence. Conclusions Despite their occupational risks of sedentary behaviour, poor diet and physical inactivity, IT workers do not have an increased cancer incidence compared to all other employed participants and the nine major SOC groups. This study paves the way for large, longitudinal health outcome studies of this under-researched and rapidly growing occupational group.


Introduction
Information technology (IT) workers are a skilled occupational group who perform any function related to IT or computer systems.Their roles include hardware, software, systems and network design/development/management, data management/ processing, helpdesk assistance and, more recently, information security, 'big data' collection and artificial intelligence [1].
IT workers have a substantially higher occupational exposure risk for sedentary work compared to the general working population (five times higher) and similar comparable occupations [2].Poor diet [3] and reduced physical activity [4] have also been reported in small, localized studies.
Prolonged sedentary behaviour is positively associated with several cancers, including colorectal, breast and endometrial [5], and higher occupational sedentary behaviour with colon and rectal cancers [6].Physical activity is strongly associated with lower cancer risk [5] and poor diet with increased cancer risk [7].
Cancer is a leading cause of morbidity and mortality, responsible for nearly one in six deaths worldwide [8].Around 30-50% of cancers are believed to be preventable through healthier lifestyles [8].High sedentary behaviour [2], poor diet [3] and reduced physical activity [4] in IT workers may impact their cancer risk yet to date, no studies have explored this.This study aims to address that knowledge gap.We evaluated incident cancer in IT workers compared with (i) the general working population and (ii) the nine major standard occupational classification (SOC) groups over a 15-year period and examined whether sociodemographic, lifestyle and occupational factors modify that association.This research is particularly relevant given the IT workforce is growing more rapidly than others [9], accounting for almost 10% of the UK workforce [9].

Methods
We conducted a population-based cohort study using UK Biobank with national cancer registry data linkage.UK Biobank is a large cohort study from across Great Britain of over 502 000 participants (6% response rate) aged 37-73 years recruited between 2006 and 2010.This entailed touch-screen questionnaire completion and face-to-face interviews with physical and biological measurements, described in detail elsewhere (https:// www.ukbiobank.ac.uk/) [2].Baseline assessment included sociodemographic, health behaviour and lifestyle data, physical measurements and employment status [2] (using SOC V.2000).
Our study population comprised IT workers and all other employed Biobank participants.Within the latter group, we categorized the nine major SOC groups (Table 2) with IT workers excluded from their respective groups.Cancer outcomes were coded according to the International Classification of Diseases ICD-9 and ICD-10.The primary outcome was defined as a first episode/incident cancer diagnosis (see Table 1, available as Supplementary data at Occupational Medicine Online, for selection codes).
Individuals who died were censored and not recorded as having an event.For each participant, follow-up commenced at the baseline UK Biobank assessment date (2006-2010) and ended on the cancer registry end dates (Table 2) unless preceded by date of death, or date of a first cancer diagnosis.
Participants with a pre-existing cancer diagnosis at baseline or the preceding years of the cancer registry, were excluded from the analysis (n = 14 352).
Having ascertained that the proportional hazards assumption had been met (using Kaplan-Meier plots), survival analyses for first/incident cancer outcomes were conducted using Cox proportional hazard regression.
Models were applied in a staged process; Model 0 was unadjusted for all covariates; Model 1 adjusted for potential confounders/socio-demographic factors; Model 2 additionally adjusted for potential mediators/lifestyle and occupational factors (see Table 2

Results
The analytical cohort comprised 272 733 employed participants, of which 10 517 (4%) were IT workers (Table 1; Figure 1, available as Supplementary data at Occupational Medicine Online).Over three-quarters of IT workers (77%) were male, with a median age of 50 years (25th/75th percentile: 45/55).Demographics of the nine major SOC groups are presented in Table 2 (available as Supplementary data at Occupational Medicine Online).
The sample size for the survival analysis for incident cancer in IT workers compared to all other employed participants was 13 351 participants, with a median survival time of 11 years (Table 2).
After adjustment for confounders, compared to all other employed participants, IT workers overall have a slightly lower cancer incidence (Model 2: hazard ratio [HR] = 0.91, 95% confidence interval [CI] 0.83-1.01).
After adjustment for confounders, compared to all major SOC groups, IT workers had a similar (Major Groups 2, 5 and 8) or lower (Major Groups 1, 3, 4, 6, 7 and 9) cancer incidence (Table 2).In both cases, CIs were wide.

Discussion
In this study, despite their known occupational risks of sedentary behaviour, poor diet and reduced physical activity, IT workers did not have an increased cancer incidence compared to all other employed participants and either of the major SOC groups.There are no published studies specifically evaluating cancer risk in IT workers to compare our results with, and further research using other cohorts is needed to replicate our findings.Longer follow-up studies are also needed, given the prolonged latency period of cancers.
This UK-based study is the first to examine cancer risk in IT workers, with a rich characterization of variables.It is not restricted to a single IT company or sector, providing a more generalizable overview of the risks of IT work.
Low response rates, healthy-worker effect and selection bias are potential limitations in UK Biobank, although studies suggest that risk factor associations in this cohort seem to be generalizable [10].Lower numbers in some of the major SOC group comparisons reduced power and there were insufficient numbers in our dataset to investigate site-specific cancers.While we accounted for socio-economic factors/potential confounders in our models, residual confounding remains possible.

Key learning points
What is already known about this subject: • The information technology revolution has seen a rapid growth in the information technology workforce, yet studies of their non-communicable disease risk, notably cancer, are lacking.• To date, there are no published studies specifically investigating cancer risk in information technology workers.

What this study adds:
• In this, the first study investigating cancer risk in information technology workers, despite their known occupational risks of sedentary behaviour, poor diet and physical inactivity, information technology workers did not have an increased cancer incidence compared to all other employed participants and the nine major Standard Occupational Classification groups.
What impact this may have on practice, policy or procedure: • While further research is needed to replicate our findings, this study sets a baseline in our understanding of information technology worker cancer risk and paves the way for further large, longitudinal health outcome studies in this occupational group.
This study sets baseline in our understanding of IT worker cancer risk.The methodology used (i.e.studying specific occupational groups using administrative and linked data) can be replicated for studies on other groups with similar or different occupational risk factors for cancer.This study also paves the way for further large, longitudinal studies to investigate other health outcomes in IT workers.This will have important implications for targeting and informing workplace interventions to mitigate risk.
; Table3, available as Supplementary data at Occupational Medicine Online).