The Association between Cholesterol and Death from Injury

PURPOSE: To review the association between low serum cholesterol and death from injury. DATA SOURCES: Relevant English-language papers identified through MEDLINE and Current Contents searches and bibliographies of identified articles. STUDY SELECTION: More than 150 articles were reviewed to identify data, meta-analyses, or important reviews of the association between low cholesterol and injuries. DATA EXTRACTION: Estimates of the association between cholesterol and death from injury were extracted from published reports. DATA SYNTHESIS: Animal studies and descriptive studies have provided little information about serum cholesterol and injuries. The Conference on Low Blood Cholesterol pooled results from 14 cohort studies in men and found a relative risk of 1.4 for death from injury in men whose cholesterol levels were lower than 4.14 mmol/L (160 mg/dL) compared with men whose cholesterol levels were 4.14 to 5.15 mmol/L (P = 0.003). Most cohort studies support this finding. The strongest evidence that cholesterol and death from injury are related comes from a meta-analysis of six randomized cardiac primary prevention trials of cholesterol reduction; the relative risk for death from injury for treated men compared with controls was 1.42 (95% Cl, 0.94 to 2.15). CONCLUSIONS: In cohort studies, the strength of the association between low serum cholesterol levels and subsequent death from injury is weak and may be caused by confounding factors such as socioeconomic status. The modestly elevated risk ratio found in a meta-analysis of trials of cholesterol reduction in men is of borderline statistical significance. This association may be related to efforts to lower cholesterol rather than to low absolute levels of serum cholesterol. Until more data are available, the hypothesized relation between low cholesterol and injuries remains unsettled.