Low total serum cholesterol is associated with an increased likelihood of school suspensions and expulsions among non-African American children, said Jian Zhang, M.D., of the University of South Carolina, Columbia, and associates.
The finding corroborates and extends existing literature linking low total cholesterol and aggressive behavior in adults. Low cholesterol may be a risk factor for aggressive behavior, a risk marker for other biologic substances or genotypes that predispose to such behavior, or a biologic marker for poor prognosis. In any case, if confirmed by prospective studies, these findings may assist pediatricians in contributing to schools and to violence prevention, the investigators said (Am. J. Epidemiol. 2005;161:691–9).
The data come from 4,852 children and adolescents aged 6–16 years (mean 10) whose mothers were interviewed for the Third National Health and Nutrition Examination Survey (NHANES III), conducted during 1988–1994. None attended special schools or classes as a result of intellectual or physical health impairment. Serum cholesterol was measured, and a variety of neuropsychiatric tests administered.
The proportion who had ever been suspended from school was 15.38% among children with serum cholesterol levels less than 145 mg/dL, compared with 6.25% among those with cholesterol levels of 145 mg/dL and above. After adjustment for age and gender, the odds ratio for school suspension for low vs. high cholesterol was 1.73.
On the other hand, serum cholesterol was not predictive of ever seeing a psychologist, being shy when meeting new persons, or having difficulty getting along with others, Dr. Zhang and his associates reported.
When broken down by race, the relationship remained significant only among the 3,167 non-African American children in the sample.
For that group, a history of school suspension or expulsion was approximately threefold higher for those with total cholesterol below the 25th percentile than for children with total cholesterol at or above the 25th percentile.
The association persisted after adjustment for many other factors, including cognitive and academic performance and nutrition status, which are known to place children's emotional and behavioral development at risk, they noted.
This study is the first to demonstrate a statistically significant, ethnicity-dependent association between serum cholesterol and aggressive behaviors from a national sample of noninstitutionalized, school-aged children.
Possible biologic mechanisms to explain the association between serum lipids and violence involve the role of cholesterol and fats in brain function and behavior through modification of membranes and through effects on neurotransmitter production, reuptake, and metabolism.
The racial difference seen in this study might have to do with differences in basal prevalence. African-American children have higher rates of school suspension, so the impact of cholesterol may be lower than in non-African Americans.