Two of the counties that were looked into, Bradford and Susquehanna, saw a recent, significant increase in drilling sites during this time period, while the third county, Wayne, had no drilling activity at all due to a ban on fracking within proximity to the Delaware River watershed.

The research, revealed this week within the journal PLOS ONE, checked out hospitalization charges in elements of Pennsylvania from 2007 to 2011 and located them considerably higher in areas with fracking in contrast to these with out.

However, the authors caution that more study is needed to determine how specific, individual toxicants or combinations may increase hospitalization rates.

The team then associated these categories with residents’ proximity to active wells. “At this point, we suspect that residents are exposed to many toxicants, noise, and social stressors due to hydraulic fracturing near their homes and this may add to the increased number of hospitalizations”, said senior author Reynold Panettieri, Jr., MD in a statement.

The first 25 medical categories for the hospitalization were of particular interest to the study.

The peer reviewed study, Unconventional Gas and Oil Drilling is Associated with Increased Hospital Utilization Rates, measured hospitalizations for cardiology and neurology related events within ZIP codes in three Pennsylvania counties (Bradford, Susquehanna, and Wayne) from 2007 to 2011. “This study represents one of the most comprehensive to date to link health effects with hydraulic fracturing”.

While the study doesn’t specifically link the health issues experienced in the two Pennsylvania counties to the substances or procedures used in the fracking process. “Our findings provide important clues to design epidemiological studies to associate specific toxicant exposures with health end-points”.

But opponents of fracking – including the Scottish and Welsh Governments – argue that still far too little is known about the effects of the technique, and say more research needs to be done before it is deployed in the United Kingdom. They found that rates of hospitalizations for heart and neurological problems were much higher among people who lived closer to active fracked wells. These areas have a fracked well density of over 0.79 wells per square kilometer. Other medical problems occurring in these areas were cancer, skin problems, as well as urologic. Wayne County was chosen as a control because it does not have any wells.

Researchers concede that this evidence does not prove hydraulic fracturing was the direct cause of these hospitalizations, but the trend does seem to conclude a correlation. However, the researchers say it does suggest that more study of the health risks of fracking is merited, and that the economic benefits of fracking should be weighed against healthcare costs.