Prolonged sitting in cars: prevalence, socio-demographic variations, and trends.
BACKGROUND
Prolonged sitting is detrimentally associated with health outcomes. However, the prevalence and characteristics of those who sit in cars for long periods are not well understood. This study examined the population prevalence, socio-demographic variations, and trends for prolonged sitting in cars among adults.


METHODS
Using the Sydney Greater Metropolitan Area Household Travel Survey, the prevalence of prolonged sitting time in cars (≥2 h/day) was calculated for four 3-year periods (1997-99, 2000-02, 2003-05, and 2006-08) for each population subgroup. Trends were calculated as the mean change in prevalence between adjacent survey periods.


RESULTS
Cars were used for 66% of the total trips recorded (n=336,505). The prevalence of prolonged sitting time in cars was 16-18% in men, and 10-12% in women. Relatively higher prevalence rates were found among middle-age groups (men: 20-22%, women: 12-15%), full-time workers (men: 21-24%, women: 14-15%), those with higher income (men: 21-25%, women: 14-16%), couples with children (men: 20-21%, women: 12-14%), and those living in outer suburbs (men: 20-23%, women: 12-13%). Trends were stable in men, but increasing in women. Several subgroups (older age; living in regional suburbs) also showed increasing trends.


CONCLUSIONS
These findings provide evidence to inform integrated approaches to measurement and policy development on prolonged car use among the public health, urban planning, and transport sectors.
Behavioural Epidemiology, Baker IDI Heart and Diabetes Institute, 99 Commercial Road, Melbourne, VIC 3004, Australia. Electronic address: takemi.sugiyama@bakeridi.edu.au.
Takemi
T
Sugiyama
School of Science and Health, University of Western Sydney, Australia.
Dafna
D
Merom
Sydney School of Public Health, University of Sydney, Australia.
Hidde P
HP
van der Ploeg
Bureau of Transport Statistics, Transport for NSW, Sydney, Australia.
Grace
G
Corpuz
Sydney School of Public Health, University of Sydney, Australia.
Adrian
A
Bauman
Behavioural Epidemiology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia.
Neville
N
Owen
D000328:Adult; D001315:Australia / Q000453:epidemiology; D001336:Automobiles; D012090:Cumulative Trauma Disorders / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D011187:Posture; D015995:Prevalence; D017678:Sex Distribution; D012959:Socioeconomic Factors; D013312:Stress, Physiological; D014195:Travel / Q000706:statistics & numerical data* / Q000639:trends; D014505:Urban Population