The first study cited not exploring indoor air pollutants as a cause for autism. Factors such as lifestyle and nutrition were also not taken into account. (Volk et al., 2013) The second study cited the use of inhaled corticosteroids (ICS) by some of the sample children as a limitation. Because ICS reduce inflammation and oxidative stress, the spirometry tests would be influenced by their use (Liu et al., 2009). The third study states that because busy roadways offer multiple reasons for death and injury, the mortality statistics need to take this into account (Jerrett et al, 2009). Finally, the fourth study cited a limitation on the reporting of type 2 diabetes. Because the reporting was done via surveys, there is no way to know if the reports are completely accurate (Kramer,
The first study cited not exploring indoor air pollutants as a cause for autism. Factors such as lifestyle and nutrition were also not taken into account. (Volk et al., 2013) The second study cited the use of inhaled corticosteroids (ICS) by some of the sample children as a limitation. Because ICS reduce inflammation and oxidative stress, the spirometry tests would be influenced by their use (Liu et al., 2009). The third study states that because busy roadways offer multiple reasons for death and injury, the mortality statistics need to take this into account (Jerrett et al, 2009). Finally, the fourth study cited a limitation on the reporting of type 2 diabetes. Because the reporting was done via surveys, there is no way to know if the reports are completely accurate (Kramer,