In MZ pairs, the mHR in the twin with AUD was more than 4 times greater than the unaffected twin. However, the mHR in discordant MZ twins was still much less than the mHR of nearly 8 seen in the general population. Finally, above the age of 55 years, the differences in mHR between the population and relatives declined further so that by our last age period (65–70 years), no appreciable differences were seen in the mHR across all our groups with all values around 4.
