Recent studies have shown that long working hours can have adverse consequences on health and possibly trigger biological processes that mediate the relationship between long working hours and cognitive decline.
Objective:
To investigate whether long working hours and the overall duration such exposure is associated with a decline in cognitive function.
Methods:
Data obtained during the Korean Longitudinal Study on Aging (n = 2,518) during the period 2006–2018 were used to explore the relationship between long working hours and cognitive decline. Korean version of the Mini-Mental State Examination (K-MMSE) scores were used to evaluate cognitive function. Cox proportional hazard regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs), which were used to evaluate declines in K-MMSE scores over the 12-year study period.
Results:
Overall HR (95% CI) for a decline in cognitive function in long working hours group was 1.13 (0.73–1.17). When categorized by sex, women with long working hours had an HR (95% CI) of 1.50 (1.05–2.22), K-MMSE scores decreased significantly after working long hours for 5 years (p < 0.01).
Conclusion:
The study furthers understanding of the effects of long working hours on cognitive decline among female workers. Further research is required to determine the effects of long working hours on cognitive functions.
PattersonC (2018) World Alzheimer Report 2018. The State of the Art of Dementia Research: New Frontiers. Alzheimer’s Disease International, London, UK.
2.
ValenzuelaMJ, SachdevP (2006) Brain reserve and dementia: A systematic review. Psychol Med36, 441–454.
3.
SantabárbaraJ, Gracía-RebledAC, López-AntónR, TomásC, LoboE, MarcosG, LoboA (2019) The effect of occupation type on risk of Alzheimer’s disease in men and women. Maturitas126, 61–68.
4.
JormAF, RodgersB, HendersonAS, KortenAE, JacombPA, ChristensenH, MackinnonA (1998) Occupation type as a predictor of cognitive decline and dementia in old age. Age Aging27, 477–483.
5.
BokenbergerK, SjölanderA, AslanAKD, KarlssonIK, ÅkerstedtT, PedersenNL (2018) Shift work and risk of incident dementia: A study of two population-based cohorts. Eur J Epidemiol33, 977–987.
6.
MarquiéJ-C, TuckerP, FolkardS, GentilC, AnsiauD (2015) Chronic effects of shift work on cognition: Findings from the VISAT longitudinal study. Occup Environ Med72, 258–264.
7.
CarusoCC, HitchcockEM, DickRB, RussoJM, SchmitJM (2004) Overtime and extended work shifts: Recent findings on illnesses, injuries, and health behaviors. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.
8.
TrudelX, BrissonC, Gilbert-OuimetM, VézinaM, TalbotD, MilotA (2020) Long working hours and the prevalence of masked and sustained hypertension. Hypertension75, 532–538.
9.
KivimäkiM, JokelaM, NybergST, Singh-ManouxA, FranssonEI, AlfredssonL, BjornerJB, BorritzM, BurrH, CasiniA (2015) Long working hours and risk of coronary heart disease and stroke: A systematic review and meta-analysis of published and unpublished data for 603 838 individuals. Lancet386, 1739–1746.
10.
SolovievaS, LallukkaT, VirtanenM, Viikari-JunturaE (2013) Psychosocial factors at work, long work hours, and obesity: A systematic review. Scand J Work Environ Health39, 241–258.
11.
VirtanenM, FerrieJE, GimenoD, VahteraJ, ElovainioM, Singh-ManouxA, MarmotMG, KivimäkiM (2009) Long working hours and sleep disturbances: The Whitehall II prospective cohort study. Sleep32, 737–745.
12.
VirtanenM, FerrieJE, Singh-ManouxA, ShipleyMJ, StansfeldSA, MarmotMG, AholaK, VahteraJ, KivimäkiM (2011) Long working hours and symptoms of anxiety and depression: A 5-year follow-up of the Whitehall II study. Psychol Med41, 2485–2494.
13.
VirtanenM, JokelaM, MadsenIE, HansonLLM, LallukkaT, NybergST, AlfredssonL, BattyGD, BjornerJB, BorritzM (2018) Long working hours and depressive symptoms: Systematic review and meta-analysis of published studies and unpublished individual participant data. Scand J Work Environ Health44, 239–250.
14.
LaunerLJ, MasakiK, PetrovitchH, FoleyD, HavlikRJ (1995) The association between midlife blood pressure levels and late-life cognitive function: The Honolulu-Asia Aging Study. JAMA274, 1846–1851.
15.
LundbergU (2005) Stress hormones in health and illness: The roles of work and gender. Psychoneuroendocrinology30, 1017–1021.
16.
KhosroS, AlirezaS, OmidA, ForoughS (2011) Night work and inflammatory markers. Indian J Occup Environ Med15, 38.
17.
SartoriAC, VanceDE, SlaterLZ, CroweM (2012) The impact of inflammation on cognitive function in older adults: Implications for health care practice and research. J Neurosci Nurs44, 206.
18.
CaiC, VandermeerB, KhuranaR, NerenbergK, FeatherstoneR, SebastianskiM, DavenportMH (2019) The impact of occupational shift work and working hours during pregnancy on health outcomes: A systematic review and meta-analysis. Am J Obstet Gynecol221, 563–576.
19.
BannaiA, TamakoshiA (2014) The association between long working hours and health: A systematic review of epidemiological evidence. Scand J Work Enviro Health40, 5–18.
20.
ThenFS, LuckT, LuppaM, ThinschmidtM, DeckertS, NieuwenhuijsenK, SeidlerA, Riedel-HellerSG (2014) Systematic review of the effect of the psychosocial working environment on cognition and dementia. Occup Environ Med71, 358–365.
21.
VirtanenM, Singh-ManouxA, FerrieJE, GimenoD, MarmotMG, ElovainioM, JokelaM, VahteraJ, KivimäkiM (2009) Long working hours and cognitive function: The Whitehall II Study. Am J Epidemiol169, 596–605.
22.
ProctorSP, WhiteRF, RobinsTG, EcheverriaD, RocskayAZ (1996) Effect of overtime work on cognitive function in automotive workers. Scand J Work Environ Health22, 124–132.
23.
Nabe-NielsenK, GardeAH, Ishtiak-AhmedK, GyntelbergF, MortensenEL, PhungTKT, RodNH, WaldemarG, WestendorpRG, HansenÅM (2017) Shift work, long working hours, and later risk of dementia: A long-term follow-up of the Male Study. Scand J Work Environ Health43, 569–577Copenhagen.
24.
KangY, NaDL, HahnS (1997) A validity study on the Korean Mini-Mental State Examination (K-MMSE) in dementia patients. J Korean Neurol Assoc15, 300.
25.
KimS, KimY, ParkSM (2016) Body mass index and decline of cognitive function. PLOS One11, e0148908.
26.
LeeW, LimS-S, KimB, WonJ-U, RohJ, YoonJ-H (2017) Relationship between long working hours and periodontitis among the Korean workers. Sci Rep7, 1–9.
27.
ParkS, KookH, SeokH, LeeJH, LimD, ChoD-H, OhS-K (2020) The negative impact of long working hours on mental health in young Korean workers. PloS One15, e0236931.
28.
OchiaiY, TakahashiM, MatsuoT, SasakiT, FukasawaK, ArakiT, TsuchiyaM, OtsukaY (2020) Objective and subjective working hours and their roles on workers’ health among Japanese employees. Ind Health58, 265–275.
29.
LiZ, DaiJ, WuN, JiaY, GaoJ, FuH (2019) Effect of long working hours on depression and mental well-being among employees in Shanghai: The role of having leisure hobbies. Int J Environ Res Public Health16, 4980.
30.
ChoiSB, YoonJ-H, LeeW (2020) The Modified International Standard Classification of Occupations defined by the clustering of occupational characteristics in the Korean Working Conditions Survey. Ind Health58, 132–141.
31.
LouridaI, HannonE, LittlejohnsTJ, LangaKM, HyppönenE, KuźmaE, LlewellynDJ (2019) Association of lifestyle and genetic risk with incidence of dementia. JAMA322, 430–437.
32.
SrivareeratM, TranTT, AlzoubiKH, AlkadhiKA (2009) Chronic psychosocial stress exacerbates impairment of cognition and long-term potentiation in β-amyloid rat model of Alzheimer’s disease. Biol Psychiatry65, 918–926.
33.
KangJ-E, LimMM, BatemanRJ, LeeJJ, SmythLP, CirritoJR, FujikiN, NishinoS, HoltzmanDM (2009) Amyloid-β dynamics are regulated by orexin and the sleep-wake cycle. Science326, 1005–1007.
34.
OomsS, OvereemS, BesseK, RikkertMO, VerbeekM, ClaassenJA (2014) Effect of 1 night of total sleep deprivation on cerebrospinal fluid β-amyloid 42 in healthy middle-aged men: A randomized clinical trial. JAMA Neurol71, 971–977.
35.
RothmanSM, HerdenerN, FrankolaKA, MughalMR, MattsonMP (2013) Chronic mild sleep restriction accentuates contextual memory impairments, and accumulations of cortical Aβ and pTau in a mouse model of Alzheimer’s disease. Brain Res1529, 200–208.
LiR, SinghM (2014) Sex differences in cognitive impairment and Alzheimer’s disease. Front Neuroendocrinol35, 385–403.
38.
MurciaM, ChastangJ-F, NiedhammerI (2013) Psychosocial work factors, major depressive and generalised anxiety disorders: Results from the French national SIP study. J Affect Disord146, 319–327.
39.
GiorgiG, LeccaLI, Leon-PerezJM, PignataS, TopaG, MucciN (2020) Emerging issues in occupational disease: Mental health in the aging working population and cognitive impairment—a narrative review. Biomed Res Int2020, 1742123.
40.
WatanabeK, ImamuraK, KawakamiN (2016) Working hours and the onset of depressive disorder: A systematic review and meta-analysis. Occup Environ Med73, 877–884.
41.
HeinrichHW (1941) Industrial Accident Prevention. A Scientific Approach. McGraw-Hill, New York.
42.
DembeAE, EricksonJB, DelbosRG, BanksSM (2005) The impact of overtime and long work hours on occupational injuries and illnesses: New evidence from the United States. Occup Environ Med62, 588–597.
43.
FolkardS, LombardiDA (2006) Modeling the impact of the components of long work hours on injuries and “accidents”. Am J Ind Med49, 953–963.
44.
Organization for Economic Cooperation and Development (2018) Hours worked. https://data.oecd.org
45.
AhnS-M, KimT-H, LeeS, KimD, GhangH, KimD-S, KimB-C, KimS-Y, KimW-Y, KimC (2009) The first Korean genome sequence and analysis: Full genome sequencing for a socio-ethnic group. Genome Res19, 1622–1629.
46.
Arevalo-RodriguezI, SmailagicN, i FigulsMR, CiapponiA, Sanchez-PerezE, GiannakouA, PedrazaOL, CospXB, CullumS (2015) Mini-Mental State Examination (MMSE) for the detection of Alzheimer’s disease and other dementias in people with mild cognitive impairment (MCI). Cochrane Database Syst Rev2015, CD010783.
47.
MitchellAJ (2013) The Mini-Mental State Examination (MMSE): An update on its diagnostic validity for cognitive disorders. In Cognitive screening instruments. Springer, pp. 15-46.
48.
DorszewskaJ, PrendeckiM, OczkowskaA, DezorM, KozubskiW (2016) Molecular basis of familial and sporadic Alzheimer’s disease. Curr Alzheimer Res13, 952–963.
