Mortality decrease according to socioeconomic groups during the economic crisis in Spain: a cohort study of 36 million people.

BACKGROUND: Studies of the effect of macroeconomic fluctuations on mortality in different socioeconomic groups are scarce and have yielded mixed findings. We analyse mortality trends in Spain before and during the Great Recession in different socioeconomic groups, quantifying the change within each group.

METHODS: We did a nationwide prospective study, in which we took data from the 2001 Census. All people living in Spain on Nov 1, 2001, were followed up until Dec 31, 2011. We included 35 951 354 people alive in 2001 who were aged between 10 and 74 years in each one of the four calendar years before the economic crisis (from 2004 to 2007) and in each one of the first four calendar years of the crisis (from 2008 to 2011), and analysed all-cause and cause-specific mortality in those people. We classified individuals by socioeconomic status (low, medium, or high) using two indicators of household wealth: household floor space (<72 m2 , 72-104 m2 , and >104 m2 ) and number of cars owned by the residents of the household (none, one, and two or more). We used Poisson regression to calculate the annual percentage reduction (APR) in mortality rates during 2004-07 (pre-crisis) and 2008-11 (crisis) in each socioeconomic group, as well as the effect size, measured by the APR difference between the pre-crisis and crisis period.

FINDINGS: The annual decline in all-cause mortality in the three socioeconomic groups was 1·7% (95% CI 1·2 to 2·1) for the low group, 1·7% (1·3 to 2·1) for the medium group, and 2·0% (1·4 to 2·5) for the high group in 2004-07, and 3·0% (2·5 to 3·5) for the low group, 2·8% (2·5 to 3·2) for the medium group, and 2·1% (1·6 to 2·7) for the high group in 2008-11 when individuals were classified by household floor space. The annual decline in all-cause mortality when people were classified by number of cars owned by the household was 0·3% (-0·1 to 0·8) for the low group, 1·6% (1·2 to 2·0) for the medium group, and 2·2% (1·6 to 2·8) for the high group in 2004-07, and 2·3% (1·8 to 2·8) for the low group, 2·4% (2·0 to 2·7) for the medium group and 2·5% (1·9 to 3·0) for the high group in 2008-11. The low socioeconomic group showed the largest effect size for both wealth indicators.

INTERPRETATION: In Spain, probably due to the decrease in exposure to risk factors, all-cause mortality decreased more during the economic crisis than before the economic crisis, especially in low socioeconomic groups.

FUNDING: None.