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Etiology

Low cholesterol levels were associated with suicide in men

ACP J Club. 1997 Mar-Apr;126:50. doi:10.7326/ACPJC-1997-126-2-050


Source Citation

Zureik M, Courbon D, Ducimetière P. Serum cholesterol concentration and death from suicide in men: Paris prospective study I. BMJ. 1996 Sep 14;313:649-51.


Abstract

Objective

To determine whether low or changing serum cholesterol levels are associated with the risk for suicide in men.

Design

Cohort study of men with mean follow-up of 17 years (Paris protective study I).

Setting

Paris, France.

Participants

7746 men who worked for the city of Paris were enrolled in the study. They were native born, aged 43 to 52 years at baseline (1967 to 1972), and had annual cholesterol examinations for up to 4 years after enrollment. 6728 men who had a minimum of 3 cholesterol measurements were studied. Follow-up was until January 1994 or death (95% follow-up).

Assessment of risk factors

Cholesterol levels were taken as the mean of all available measurements and were categorized into 3 levels (low, < 4.78 mmol/L; normal, 4.78 to 6.21 mmol/L; and high, > 6.21 mmol/L). Mean annual change in cholesterol levels was calculated using within-person, linear regression. These mean annual changes were categorized as a decline of > 0.13 mmol/L, change of ≤ 0.13 mmol/L, or an increase of > 0.13 mmol/L per year. Data were adjusted for age, smoking, and mean corpuscular volume.

Main outcome measures

Suicide data were taken from national databases and death certificates.

Main results

13% of the men had low cholesterol levels, 56% had normal levels, and 31% had high levels; 18% had decreasing levels, 44% had stable levels, and 38% had increasing levels. 32 men committed suicide during follow-up. Compared with men who had cholesterol levels of 4.78 to 6.21 mmol/L, men in the lower cholesterol level group (< 4.78 mmol/L) had an increased risk for suicide (relative risk [RR] 3.16, 95% CI 1.38 to 7.22, P = 0.007). Higher levels of cholesterol were not associated with suicide (RR 1.28, CI 0.55 to 3.01, P = 0.56). Compared with stable levels of cholesterol (change of ≤ 0.13 mmol/L per y), decreasing levels of cholesterol (RR 2.17, CI 0.97 to 4.84, P = 0.06) or increasing levels of cholesterol (RR 0.72, CI 0.30 to 1.72, P = 0.46) were not associated wiyh suicide. In men with normal or low cholesterol levels, however, declining cholesterol levels (compared with stable or increasing levels) were associated with suicide (RR 2.78, CI 1.13 to 6.82, P = 0.03).

Conclusion

Low mean cholesterol levels and declining cholesterol levels combined with normal or low cholesterol levels were associated with an increased risk for suicide in men.

Source of funding: No external funding.

For article reprint: Dr. M. Zureik, National Institute of Health and Medical Research (INSERM), Unit 258, Hôpital Broussais, 96 rue Didot, 75014-Paris, France. FAX 33-1-45-43-42-69.


Commentary

Zureik and colleagues present an observational study designed to assess cardiovascular risk factors. It was not specifically designed to test the hypothesis that low or changing cholesterol levels are related to suicide rates; however, the results did show an association between low serum cholesterol levels and increased suicide rates. This type of analysis of a secondary data set has fundamental problems, including a lack of appropriate stratification for occupation, income level, and comorbid conditions.

Longitudinal follow-up of a cohort of participants leaves us with another hypothesis-generating exercise that catches the attention of the media and may bring a wave of the "worried well" to their physicians asking for tests for low serum cholesterol levels.

The subgroup finding of this study, that suicide was associated with declining cholesterol levels in men with normal or low cholesterol levels, might seem worrisome for interventions intended to lower cholesterol. Fortunately, recent randomized trials of cholesterol-lowering agents do not bear this out (1).

It is inappropriate to infer any cause-and-effect relation based on this study. It simply adds a little more mud to the waters stirred up by previous investigations (1-3).

Walter W. Rosser, MD
University of TorontoToronto, Ontario, Canada

Walter W. Rosser, MD
University of Toronto
Toronto, Ontario, Canada


References

1. Law M. Commentary: Having too much evidence (depression, suicide, and low serum cholesterol). BMJ. 1996;313:651-2.

2. Neaton JD, Blackburn H, Jacobs D, et al. Serum cholesterol level and mortality findings for men screened in the Multiple Risk Factor Intervention Trial. Arch Intern Med. 1992; 152:1490-500.

3. Lindberg G, Råstam L, Gullberg B, Eklund GA. Low serum cholesterol concentration and short term mortality from injuries in men and women. BMJ. 1992;304:277-9.