Title:
Occupational mobility and carotid artery intima-media thickness: findings from the Coronary Artery Risk Development in Young Adults Study.

Abstract:
To examine whether a 10-year change in occupational standing is related to carotid artery intima-media thickness (IMT) 5 years later.
Data were obtained from 2350 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Occupational standing was measured at the Year 5 and 15 CARDIA follow-up examinations when participants were 30.2 (standard deviation = 3.6) and 40.2 (standard deviation = 3.6) years of age, respectively. IMT (common carotid artery [CCA], internal carotid artery [ICA], and bulb) was measured at Year 20. Occupational mobility was defined as the change in occupational standing between Years 5 and 15 using two semicontinuous variables. Analyses controlled for demographics, CARDIA center, employment status, parents' medical history, own medical history, Year 5 Framingham Risk Score, physiological risk factors and health behaviors averaged across the follow-up, and sonography reader.
Occupational mobility was unrelated to IMT save for an unexpected association of downward mobility with less CCA-IMT (β = -0.04, p = .04). However, associations differed depending on initial standing (Year 5) and sex. For those with lower initial standings, upward mobility was associated with less CCA-IMT (β = -0.07, p = .003), and downward mobility was associated with greater CCA-IMT and bulb-ICA-IMT (β = 0.14, p = .01 and β = 0.14, p = .03, respectively); for those with higher standings, upward mobility was associated with greater CCA-IMT (β = 0.15, p = .008), but downward mobility was unrelated to either IMT measure (p values > .20). Sex-specific analyses revealed associations of upward mobility with less CCA-IMT and bulb-ICA-IMT among men only (p values < .02).
Occupational mobility may have implications for future cardiovascular health. Effects may differ depending on initial occupational standing and sex.