Broad societal determinants of CVD and health Dubai 6/1/2006

Issues for the Pure study Health transition (Britain as an example) Gender differences during health transition At what age does the influence of broad social factors on adult disease start? (Income inequality, social capital, social comparison) Is a prospective study necessary? Contingent causes, proximal causes and understanding mechanisms

Preston. Population Studies, 1975 Economic development and health: selection of the Pure study countries may determine the answers

Health transition, coronary heart disease and stroke in Britain Different trajectories in men and women over time, and socio-economic patterning changing

CVD trends (from Lawlor et al BMJ 2001)

Coronary Heart Disease and stroke share risk factors Raised blood pressure High blood cholesterol Smoking Insulin resistance / diabetes Physical inactivity

The paradox So – if coronary heart disease and stroke share risk factors – Why are the secular trends different? –And why no epidemic of stroke during the 20 th century?

What caused the epidemic of coronary heart disease? Increased intake of dietary fat Increase in smoking Increase in obesity? Decrease in physical activity? BUT Secular decline in blood pressure

Stroke: two major pathologies Haemorrhage Ischaemia

which are rather different… haemorrhage Ischaemia

but look the same to doctors…

Ischaemia:haemorrhage ratio Year Ischaemia:haemorrhage ratio, autopsy data Fitted values Lawlor et al. Lancet 2002 Ratio of ischaemia to haemorrhage,1930 to 2000

Mortality / Year Total stroke rate Estimated haemorrhagic rate Estimated ischaemic rate Stroke trends by sub-type Lawlor et al. Lancet 2002

Risk factors by stroke subtype Haemorrhagic Blood pressure +++ Smoking +/- Cholesterol – Obesity + Ischaemic Blood pressure ++ Smoking +++ Cholesterol +++ Obesity ++

Changing social distribution of CVD risk factors

Moteiro CA. Bull WHO 2004;82:940-6

Age of influence of socio- environmental factors for blood pressure

Blood pressure trends Marked declines among 18 year olds from in UK Clear cohort effects in declines in blood pressure in U.S.

Early life influences on adult blood pressure Adverse social circumstances Low birthweight Poor height gain in early childhood (especially in leg length) Artificial feeding Infancy sodium intake ? Low physical activity / obesity ? Lawlor and Davey Smith. Current Opinion in Nephrology and Hypertension 2005;14:259-64

Childhood social class and stroke subtype: Manual vsManual vs + non-manualnon-manual Haemorrhagic2.84 ( )3.22 ( ) Ischaemic1.25 ( )0.92 ( ) + risk factor adjusted Hart and Davey Smith; J Epidemiol Community Health 2003

Height quintileRR associated with 10 cm increase in height All stroke Relative rate (0.73 to 0.88) Haemorrhagic Relative rate (0.51 to 0.97) Ischaemic Relative rate (0.71 to 1.06) Stroke by height: Paisley and Renfrew study McCarron et al. J Epidemiol Community Health 2001;55:

Stroke subtype by number of siblings per sibper sib + Haemorrhagic Ischaemic adjusted SEP and risk factors Hart and Davey Smith, J Epidemiol Community Health 2003

Systolic blood pressure mmHg (mean, 95% CI) Systolic blood pressure a Diastolic blood pressure Diastolic blood pressure a Dehydration admission No dehydration admission Difference1.5 (-5.8, 8.9)2.5 (-4.3, 9.3)5.9 (0.6, 11.3)6.2 (1.04, 11.4) P difference a adjusted for sex, age, height and BMI at the time of blood pressure measurement, birthweight and gestation, maternal education Davey Smith et al JECH, in press

Income inequality, social capital, social comparison

Comparing Canada and the U.S.

Ross, et al., BMJ (2000) Canada Paradox?

Ross, et al (unpublished)

American “exceptionalism”?

Material conditions or social comparison?

Check-In Seat Leg Room Food Service Sleeping Health Relevant Material Conditions? What generates health inequalities after a long airline flight? Or: seeing Martin McKee in business class?

Measures of social position can give some insight..

Unadjusted Odds Ratios and percent reduction of elevated risk on adjustment for mortality by caste and standard of living index Infant (<1 year) CasteStandard of living index Other Caste1.00-Top fifth1.00- SC %Fourth fifth % ST %Third fifth % OBC %Second fifth % No Caste1.3944%Bottom fifth % Subramanian et al, AJPH, in press

Unadjusted Odds Ratios and percent reduction of elevated risk on adjustment for mortality by caste and standard of living index Young adult (19-44 years) CasteStandard of living index Other Caste1.00-Top fifth1.00- SC %Fourth fifth % ST %Third fifth1.91 0% OBC %Second fifth2.11 2% No Caste %Bottom fifth3.00 4%

Unadjusted Odds Ratios and percent reduction of elevated risk on adjustment for mortality by caste and standard of living index Middle-aged adult (45-64 years) CasteStandard of living index Other Caste1.00-Top fifth1.00- SC %Fourth fifth % ST %Third fifth % OBC %Second fifth % No Caste %Bottom fifth %

Is a prospective study necessary?

Bias Illustrations of how bias can generate associations between self-reported exposures and outcomes

Relative rates for CHD outcomes according to stress Incident Incident CHD Stressanginaischaemia mortality High Medium Low p for trend< Macleod et al BMJ 2001

Reporting tendency, angina and psychological stress Perceived stressMean reporting tendency score Incident angina Odds ratios Adjustment AAdjustment B High Medium Low p for trend< Macleod J et al. JECH 2002;56:76-77

Job control Odds ratio for incident “Rose” angina Low control 2.02 ( ); Intermediate control 1.44 ( ); High control 1.00 Bosma et al. BMJ 1997;314:

Fully subjective High Exposure 2.66 Medium Exposure 1.37 Low Exposure 1.00 High Exposure 2.02 Medium Exposure 1.44 Low Exposure 1.00 Partially subjective High Exposure 1.20 Medium Exposure 1.03 Low Exposure 1.00 High Exposure 1.65 Medium Exposure 1.13 Low Exposure 1.00 Fully objective High Exposure 0.67 Medium Exposure 1.03 Low Exposure 1.00 High Exposure 1.17 Medium Exposure 1.16 Low Exposure 1.00 Macleod J et al. BMJ 2002;324: Bosma H et al. BMJ 1997;314: Stansfeld SA et al. Int J Epidemiology 2002;31:

Contingent causes, proximal causes and understanding mechanisms

TIME CB OUTCOMEMEASUREOUTCOMEMEASURE Contingent links Context dependent underlying factors

TIME LUNGCANCERLUNGCANCER Contingent links Social positionSmoking

TIME OUTCOMEMEASUREOUTCOMEMEASURE Contingent links Context dependent underlying factors BMI Insulin resistance