average of about 2,250 parts per billion of PFOA in their blood from a starting average of around 50 parts per billion less than a year prior. In late 2012, scientists at Emory University compared health risks in workers at a DuPont chemical plant in West Virginia with high PFOA exposure to the risks of the same diseases in other regional DuPont factory workers and in the US population. In comparison with the other DuPont workers, workers at the high-PFOA plant were at roughly three times the risk of dying of mesothelioma or chronic kidney disease, and roughly twice the risk of dying of diabetes mellitus. Workers were at similarly elevated risk for kidney cancer and for non-cancer kidney diseases. In rodents, PFOA concentrates in the kidneys. Consumers Single cross-sectional studies on consumers have been published noting multiple associations. Blood serum levels of PFOA were associated with an increased time to pregnancy—or "infertility"—in a 2009 study. PFOA exposure was associated with decreased semen quality, increased serum alanine aminotransferase levels, and increased occurrence of thyroid disease. In a study of 2003–2004 US samples, a higher (9.8 milligram per deciliter) total cholesterol level was observed when the highest quartile was compared to the lowest. Along with other related compounds, PFOA exposure was associated with an increased risk of attention deficit hyperactivity disorder (ADHD) in a study of US children aged 12–15. In a paper presented at the 2009 annual meeting of the International Society of Environmental Epidemiology, PFOA appeared to act as an endocrine disruptor by a potential mechanism on breast maturation in young girls. A C8 Science Panel status report noted an association between exposure in girls and a later onset of puberty. PFOA exposure and incident cancer research Extensive research on PFOA and its role in the causal pathway of cancers exists for animals, however human studies are rare—most studies are mortality studies, which have small sample sizes. A longitudinal study focused on residents living in Mid-Ohio Valley concluded that PFOA concentrations are positively associated with kidney and testicular cancers [hazard ratio = 1.10 and 1.34, respectively, for a 1-unit increase in log-transformed serum PFOA]. The study consisted of 32,254 residents with 2,507 reported cancer diagnoses occurring during study period. PFOA serum concentrations were measured at baseline and three to six year follow-up meetings. Retrospective yearly PFOA serum levels were estimated for each subject from 1952 through 2011. Initial subject