Public Studies

To determine the highest probable cause of death between cigarette smoking and obesity in males.

45,000 men were tested for health factors and questioned about their smoking habits for the purpose of following up with them later. During the follow up period 2,897 subjects died, the incidence of death was lowest for people with normal weight and highest in obese subjects. The risk of premature death also correlated heavily with the increase of the number of cigarettes smoked per day.

The participants all had their body mass index (BMI) measured and reported their smoking status at the age of 18 and were followed up for an average of 38 years.

Being overweight at the age of 18 increased the risk of premature death by just over a third, while being obese more than doubled the risk. Being underweight carried no increased risk, irrespective of smoking status. However, being seriously underweight (a body mass index of less than 17) carried the same risk of premature death as being overweight. The combination of obesity and heavy smoking was associated with a large excess risk of early death (almost five times greater than normal weight non-smokers). However, there was no statistically significant interaction between these two factors. This means that being overweight or obese at the age of 18 increases the risk of premature death regardless of smoking status. Early death was also linked to the number of cigarettes participants smoked per day. This risk gradually increased the more participants smoked, with heavy smokers at more than double the risk of premature death compared to non-smokers.

• [_] This study does not take into account dietary factors.
• [+] This study was peer reviewed prior to entering the Public Studies database.

To isolate a statistically significant probably cause of Autism

More than 3,000 new cases of autism were reported in California in 2006, compared with 205 in 1990. This increase does not correlate with increased willingness or ability to diagnose this condition. Changes in how and when doctors diagnose the disorder and when state officials report it can explain less than half of the increase. In 1990, 6.2 of every 10,000 children born in the state were diagnosed with autism by the age of five, compared with 42.5 in 10,000 born in 2001.

Sample analysis. Hertz-Picciotto and Lora Delwiche of the UC Davis Department of Public Health Sciences analyzed 17 years of state data that tracks developmental disabilities, and used birth records and Census Bureau data to calculate the rate of autism and age of diagnosis.

California’s sevenfold increase in autism cannot be explained by changes in doctors’ diagnoses and most likely is due to environmental exposures. The researchers have theorized that a pregnant woman’s exposure to chemical pollutants, particularly metals and pesticides, could be altering a developing baby’s brain structure, triggering autism.

[+] This study was peer reviewed at the source.
[-] This study does not isolate a single environmental substance.
[+] There has been a followup study that confirms these findings: http://www.huffingtonpost.com/stephen-barrie-nd/child-autism-epidemic-fir_b_696179.html & http://personalizedmedicine.posterous.com/environmental-factors-contributing-to-the-ons#