Table 2. Odds of developing depressive symptoms after 4 years among adults initially without depressive symptoms, based on the number of occasions inflamed (n=2068).

	Odds of developing depressive symptoms after 4 years
	Model 1 (age, sex and wealth)	Model 1+antidepressant drug usea	Model 1+BMI, chronic diseaseb, disability and cognitive impairment	Model 1+smoking and physical activity	Adjusted for all factors
	Odds ratio (95% CI)	Odds ratio (95% CI)	Odds ratio (95% CI)	Odds ratio (95% CI)	Odds ratio (95% CI)
Inflammatory status
Inflamed on zero occasions (n=1200)	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)	1.00 (reference)
Inflamed on one occasion (n=461)	1.03 (0.64, 1.65)	1.03 (0.64, 1.65)	0.98 (0.61, 1.60)	0.98 (0.61, 1.58)	0.96 (0.59, 1.56)
Inflamed on two occasions (n=407)	1.85 (1.22, 2.80)	1.78 (1.17, 2.71)	1.74 (1.10, 2.75)	1.68 (1.10, 2.57)	1.60 (1.00, 2.55)

Abbreviations: CI, confidence interval; CRP, C-reactive protein. The number of occasions inflamed considers having CRP ⩾3 mg l⁻¹ at either none of, one of or both of 2004/05 and 2008/09. Outcome defined as having depressive symptoms (more than or equal to four of eight symptoms) vs not having depressive symptoms (less than four of eight symptoms) in 2012/13. Covariates are assessed in 2008/09.

^aAntidepressant drug use based on nurse-coded drugs in 2012/13.

^bChronic disease considers prevalent/recent cardiovascular disease (myocardial infarction, angina or stroke), type 2 diabetes, cancer, osteoarthritis, rheumatoid arthritis, chronic lung disease and asthma.