on diabetes is still under investigation. They may impair the metabolism of long-chain polyunsaturated fatty acids (LCPUFAs), but maternal pregnancy trans fatty acid intake has been inversely associated with LCPUFAs levels in infants at birth thought to underlie the positive association between breastfeeding and intelligence. Consumption of industrial trans fat in the form of partially hydrogenated oil causes many health problems. They were abundant in fast food restaurants. They are consumed in greater quantities by people who lack access to a diet consisting of fewer partially-hydrogenated fats, or who often consume fast food. A diet high in trans fats can contribute to obesity, high blood pressure, and higher risk for heart disease. Trans fat is also implicated in Type 2 diabetes. Coronary artery disease The most important health risk identified for trans fat consumption is an elevated risk of coronary artery disease (CAD). A 1994 study estimated that over 30,000 cardiac deaths per year in the U.S. are attributable to the consumption of trans fats. By 2006 upper estimates of 100,000 deaths were suggested. A comprehensive review of studies of trans fats published in 2006 in the New England Journal of Medicine reports a strong and reliable connection between trans fat consumption and CAD, concluding that "On a per-calorie basis, trans fats appear to increase the risk of CAD more than any other macronutrient, conferring a substantially increased risk at low levels of consumption (1 to 3% of total energy intake)". The major evidence for the effect of trans fat on CAD comes from the Nurses' Health Study – a cohort study that has been following 120,000 female nurses since its inception in 1976. In this study, Hu and colleagues analyzed data from 900 coronary events from the study's population during 14 years of followup. He determined that a nurse's CAD risk roughly doubled (relative risk of 1.93, CI: 1.43 to 2.61) for each 2% increase in trans fat calories consumed (instead of carbohydrate calories). By contrast, for each 5% increase in saturated fat calories (instead of carbohydrate calories) there was a 17% increase in risk (relative risk of 1.17, CI: 0.97 to 1.41). "The replacement of saturated fat or trans unsaturated fat by cis (unhydrogenated) unsaturated fats was associated with larger reductions in risk than an isocaloric replacement by carbohydrates." Hu also reports on the benefits of reducing trans fat consumption. Replacing 2% of food energy from trans fat