Publications

INTRODUCTION

Tobacco-attributable deaths contribute significantly to the increased mortality observed among homeless adults aged 50 years or more. Little is known about the epidemiology of tobacco use among older homeless individuals. This longitudinal cohort study examines smoking behaviors and factors associated with smoking cessation among homeless individuals aged 50 years or more.

METHODS

We recruited a prospective cohort of 350 homeless individuals sampled from the community in Oakland, California. At 6 months follow-up, participants reported their cigarette quit attempts and 30-day abstinence. We used multivariable logistic regression to examine factors associated with making a quit attempt at follow-up, hypothesizing that heavier smokers would be less likely to make a quit attempt.

RESULTS

Of the 272 ever-smokers, 229 (84.2%) were current smokers (quit ratio 15.8). Among current smokers at enrollment who had a follow-up interview at 6 months, 43.6% (n = 71) reported making a quit attempt during the follow-up. Of those who reported making a quit attempt, 14.3% (n = 10) reported 30-day abstinence at follow-up. Among those who had reported making a quit attempt at follow-up, 22.5% had used nicotine replacement therapy (NRT). Staying in shelters (adjusted odds ratio [AOR] = 2.5, 95% confidence interval [CI] = 1.0-5.8) was associated with higher odds of making a quit attempt at follow-up. Higher cigarette consumption was associated with lower odds of making a quit attempt (AOR = 0.9, 95% CI = 0.8-0.9).

CONCLUSIONS

In this study of tobacco use in older homeless adults, rates of quit attempts were similar to that observed in the general population, but successful quitting was lower.

IMPLICATIONS

The current study is among the first studies to focus specifically on tobacco use and cessation behaviors among older homeless adults. The high prevalence of smoking and the low rates of successful quitting highlight numerous opportunities to intervene to increase quitting rates among this population. Among these, increasing access to smoke-free living environments and identifying effective cessation therapies will be critical to reducing tobacco-related disease burden among older homeless adults.

Ischemic preconditioning is the phenomenon whereby brief periods of sublethal ischemia protect against a subsequent, more prolonged, ischemic insult. In remote ischemic preconditioning (RIPC), ischemia to one organ protects others organs at a distance. We created mouse models to ask if inhibition of the alpha-ketoglutarate (αKG)-dependent dioxygenase Egln1, which senses oxygen and regulates the hypoxia-inducible factor (HIF) transcription factor, could suffice to mediate local and remote ischemic preconditioning. Using somatic gene deletion and a pharmacological inhibitor, we found that inhibiting Egln1 systemically or in skeletal muscles protects mice against myocardial ischemia-reperfusion (I/R) injury. Parabiosis experiments confirmed that RIPC in this latter model was mediated by a secreted factor. Egln1 loss causes accumulation of circulating αKG, which drives hepatic production and secretion of kynurenic acid (KYNA) that is necessary and sufficient to mediate cardiac ischemic protection in this setting.