1. SocioEconomic Position Contact: cristian.carmeli@chuv.ch
Socioeconomic status and 25x25 risk factors as determinants of physical functioning at older ages: a multicohort study of 109’012 participants in 24 countries
Carmeli C(1), Stringhini S(1), Jokela M(2), Avendaño M(3), Bochud M(1), Paccaud F(1), Kivimäki M(4), Vineis P(5), for the LIFEPATH consortium
(1) Division of Chronic Diseases, Institute of Social and Preventive Medicine (IUMSP), CHUV, Lausanne, CH, (2) Institute of Behavioural Sciences, University of Helsinki, FI, (3) Department of Global Health and Social Medicine, King’s College London, London, UK, (4) University College London, Department of Epidemiology and Public Health, London, UK, (5) MRC-PHE Centre for Environment and Health, School of public Health, Department of Epidemiology and Biostatistics, Imperial College London, London, UK
RESULTS
A 60-year old man with low SEP had the same walking speed as a high SEP man 6.4 years older (95% confidence interval ). The corresponding difference was 4.5 ( ) years for women. Similar YFL were associated to obesity, diabetes and physical inactivity (see figure 3). Smaller YFL were associated to current smoking, hypertension and high alcohol intake.
BACKGROUND
With population ageing, prevention of age-related diseases and functional loss has become a public health priority. In terms of morbidity and mortality, a substantial body of evidence shows the potential benefits of targeting risk factors defined in global health strategies. In contrast, few studies have examined the extent to which these factors will affect functional loss at older ages. To address this gap, we analysed the impact of adverse socioeconomic circumstances and the WHO 25x25 risk factors (smoking, diabetes, hypertension, obesity, physical inactivity and high alcohol intake) on physical functioning at older ages.
DATA & METHODS
We pooled cross-sectional individual-level data from 109,012 men and women aged 45 to 90 years from 37 cohort studies spanning 24 WHO countries in Europe, the United States, Latin America, Africa and Asia. Study baseline recruitment occurred between 1990 and 2017.
Physical functioning was assessed via the walking speed test, a validated index of overall functional capacity. The setup differed among cohorts, for instance walk distance varied from 8ft to meters. Socioeconomic status was based on occupational title (SEP) according to the ESEC scheme. Risk factors were measured either from self-report or biomarkers.
Figure 1. Flow diagram of participants in the study.
Figure 3. Years of functioning lost by 60 years of age due to suboptimal risk factors. Models including only the risk factor under study are called minimally adjusted, whilst models including all risk factors are called mutually adjusted. All models were adjusted for age, height and year of birth. Additional analyses adjusting for ethnicity and baseline health status provided results similar to the main ones.
We computed years of functioning lost (YFL) attributable to low SEP and suboptimal risk factors to quantify the gap in physical aging with reference subpopulations (see figure 2).
Analysis stratified by countries’ income revealed a heterogeneity (see Table 1), in particular for low SEP. This could be explained by misclassification of SEP in low/middle income countries due to large fractions of the population in the informal economy, or by different social patterning of major risk factors for loss of functional capacity.
SocioEconomic Position
(high, middle, low)
Body Mass Index
(normal, overweight, obese)
Alcohol Intake
(moderate, abstainer, high)
MEN
WOMEN
High Income
LMICs
Risk Factor
YFL (95% CI)
Low SEP
-7.8 (-13.2; -5.6)
-2.4 (-6.6; -0.2)
-5.4 (-8.0; -4.0)
-2.7 (-5.5; -1.0)
Obesity
-5.6 (-8.8;-4.0)
-5.2 (-11.7; -2.1)
-8.3 (-11.2; -6.5)
-6.6 (-11.6; -4.3)
Current Smoking
-5.0 (-7.9;-3.6)
0.7 (-1.1; 3.5)
-1.4 (-2.5; -0.7)
2.6 (0.7; 5.6)
High Alcohol Intake
-1.0 (-2.0; -0.1)
3.6 (-0.4; 12.4)
0.1 (-0.9; 1.1)
0.0 (-8.3; 7.7)
Hypertension
-2.5 (-4.3; -1.7)
-3.4 (-8.1; -1.6)
-3.4 (-5.1; -2.5)
-4.3 (-7.9; -2.5)
Diabetes
-6.2 (-9.9; -4.4)
-6.2 (-13.0; -3.0)
-8.5 (-12.7; -6.4)
-4.6 (-8.6; -2.4)
Physical Inactivity
-5.8 (-9.2; -4.2)
-8.5 (-17.1; -4.9)
-6.4 (-9.3; -4.9)
-4.1 (-7.0; -2.5)
Smoking Status
(never, past, current)
Hypertension
(no, yes)
T2 Diabetes
(no, yes)
Physical Inactivity
(no, yes)
High SEP
Low SEP
Age [years]
Walking speed [m/s]
Walking Speed Test
YFL ≈ -7 years
Table 1. Years of functioning lost by 60 years of age due to suboptimal risk factors – comparison between high income and low/middle income countries (LMICs).
CONCLUSIONS
Socioeconomic disadvantage and the 25x25 risk factors, in particular physical inactivity, obesity and diabetes, significantly reduce physical functioning already by age 60.
We suggest that addressing these risk factors globally will likely bring major public health benefits in terms of expanding both years of life as well as years spent in good physical functioning.
Future work should address other aspects of physical and/or cognitive functioning, and confirm our findings through longitudinal/repeated measures data.
Figure 2. Years of functioning lost by age 60 for low SEP participants. Walking speed trajectories are the average-population predictions of a mixed model with study and walk distances as random effects.
Reference: Stringhini S, Carmeli C, et al. BMJ 2018;360:k1046
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