We assessed for associations of ever smoked (1 = current or former smoking on most or all days, 0 = never smoking on most or all days), cigarettes per day (present if they are currently smoking or past if they are no longer smoking), and smoking duration (age at the time of data collection minus the year they started smoking if they are currently smoking, and the year they stopped smoking minus the year they started smoking if they are no longer smoking) with gray matter and white matter controlling for age, sex, ethnicity, income, college degree, alcoholic drinks per month, body mass index, waist-hip ratio, diastolic and systolic blood pressure, and x , y , z position in the scanner
1, 271272.10.1038/1082 45 HajekP.JacksonP.BelcherM
However, observational studies cannot be used to reliably identify causality due to limitations such as residual confounding and reverse causality 17
In 2007, on the Navajo Nation, of the 329 rape cases reported among a population of 180,000 individuals, only 17 arrests were made in five years
