Cross-cultural associations:

Average serum cholesterol level and 25-year CHD death rates in the 16 cohorts

In the 1960s average serum cholesterol levels varied from 160 mg/dl (4 mmol/l) in the Japanese cohorts to 270 mg/dl (7 mmol/l) in Eastern Finland. The baseline serum cholesterol levels of the 16 cohorts were positively correlated with the CHD mortality rates after 5, 10, and 25 years. The higher the average serum cholesterol level at baseline the higher the CHD mortality rates. Cohorts with low serum cholesterol levels at outset, in which average levels rose during 10 years of follow-up had an excess risk of CHD mortality during the subsequent 15 years.

Serum cholesterol levels were correlated to long-term CHD mortality

Average serum cholesterol and CHD rates

Interpretation

These results indicate that both average serum cholesterol level and change in this level are correlated with CHD mortality rate in the 16 cohorts of the SCS. Individual 25-year risk of CHD death within SCS cohorts was also strongly related to serum cholesterol level. Because primary and secondary prevention trials have shown that reduction of serum cholesterol levels (with statins) reduced risk of CHD events and death, the totality of evidence is strong that serum cholesterol is causally related to CHD mortality.

References

More cohort findings with 25 or 50-year follow-up in the 16 cohorts

The original cross-cultural associations from the 1960s were later repeated using 25 and 50-year CHD mortality data for serum cholesterol and saturated fat intake and extended with associations on flavonoids and dietary patterns.

25-year follow-up study findings

50-year follow-up study findings

Are these cross-cultural associations causal?

Ecological or cross-cultural associations are frequently viewed as the lowest level of evidence about causality. However, to demean ecological associations is to fail to recognize the powerful indication they provide about the population burden of disease. They can be useful for prevention when correlations among populations are congruent with sound clinical evidence, with significant correlations at the level of individuals within populations, and with known mechanisms.

Read more about cross-cultural findings

Search study findings on the individual level:

Alcohol (6) All-cause mortality (16) Blood pressure (8) Body mass index (7) Cardiovascular disease (30) Cholesterol (8) Cohort (12) CVD risk factors (31) Depression & Optimism (11) Diabetes (6) Diet (23) Dietary patterns (4) Disease outcomes (13) ECG predictors (2) Fatty acids (5) Flavonoids & lignans (5) Foods (7) Functional outcomes (10) Healthy aging (38) Lifestyle (25) Mental health (11) Nutrients (8) Physical activity (9) Self-rated health (2) Smoking (11)