During the past several years many studies have shown that childhood IQ is highly correlated with adult health and longevity, e.g. see story about recent article in the journal Pediatrics:
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In California and elsewhere in the USA (and in international comparisons between countries), racial groups tend to differ in IQ, socioeconomic position (social class), and health. with Asians (especially Chinese, Koreans, and Japanese) tending to show higher IQ, socioeconomic position, and health than whites. Conversely blacks tend to show lower IQ, socioeconomic position,and health compared with whites.

With Hispanics (especially those with full or partial Native American ancestry from Mexico and South America), the pattern is different with Hispanics showing lower IQ and socioeconomic position compared with whites, but yet these Hispanics still tend to show lower mortality than whites. This is known as the Hispanic Paradox. For more info just google hispanic paradox, or check this recent article: <link>

Recently a pathologist from Univ of Pittsburgh has proposed a "CHRM2 vagal vigor" theory to explain how differences in the CHRM2 gene may contribute to racial differences in cognitive ability and health. A pdf copy of his hypothesis (Cognitive epidemiology of ethnic health and the CHRM2 vagal vigour hypothesis) is available at the Nature Precedings website at this link:
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