Table 1 Summary of included studies on smoking associated with subsequent frailty status change among community-dwelling older people

Woods et al., 2005 [18]

USA

28,181

65–79

100 %

never, past, current smoking

Incident frailty by modified Fried criteria

3 years

- Past smoking was associated with incident frailty (OR = 1.12 95 % CI = 1.02–1.23), but not prefrailty (OR = 0.95 95 % CI = 0.89–1.02).

- Current smoking was associated with both incidence frailty (OR = 1.76 95 % CI = 1.49–2.09) and prefrailty (OR = 2.90 95 % CI = 2.35–3.57)

- Unadjusted multinomial logistic regression.

Ottenbacher et al., 2009 [17]

USA

777

82.5

56.4 %

never, past, current smoking

Fried frailty score (range: 0–5)

10 years

- “Ever smoked” was associated with increase in frailty score at follow-up (beta = 0.36, SE = 0.15, p < 0.05)

- Linear regression adjusted for age, gender, education, married, financial strain, diabetes, hip fracture, cancer, stroke, cardiac diseases, arthritis, body mass index and baseline frailty.

Wang et al., 2013 [23]

China

3257

70.1

51.1 %

never, current/past smoking

Frailty index

15 years

- Current/past smoking was associated with increase in frailty at follow-up (beta = 3.64, SE = 1.62, p = 0.03) in men.

- No such association was observed in women.

- Linear regression adjusted for age, education, baseline frailty index.

Lee et al., 2014 [24]

China

3018

73.6

49.7 %

never, past, current smoking

Change in frailty Category change by Fried criteria

2 years

- No significant association was observed.

- Gender-stratified age-adjusted logistic regression

Etman et al., 2015 [25]

11 European countries

14,082

>55

54.3 %

never, past, current smoking

Worsening in frailty by Fried criteria (robust > prefrail/frail or prefrail > frail)

2 years

- Current smoking was associated with worsening of frailty status at follow-up (OR = 1.16, 95 % CI = 1.02–1.32, p < 0.05)

- Logistic regression adjusted for age, gender, education, baseline frailty and country.