Story highlights After Sandy Hook, gun sales spiked, and so did the number of accidental gun deaths

The study is one of the first to quantify accidental deaths in relation to gun sales

(CNN) After 26 children and educators were gunned down at Sandy Hook Elementary School in 2012 and President Barack Obama talked about increasing gun control, Americans bought more guns. But instead of offering protection, at least in some cases, the sales increased the chances that people would be accidentally shot and killed, according to a study published Thursday in Science magazine.

An additional 20 children and 40 adults, beyond what would be expected, died in accidental gun violence in the five-month period after Sandy Hook, the study found. This is considered a statistically significant increase during a time in which, the authors estimate, 3 million additional guns were sold beyond the general rate at which people typically buy guns.

No other spike in accidental deaths "of that magnitude" matches what happened after Sandy Hook, the authors wrote, and the states that had the biggest increase in sales saw the biggest increase in accidental gun deaths. The states with the smallest increase in gun sales saw the smallest number of additional accidental deaths.

The authors suggest that these numbers again confirm the theory that increasing access to guns increases the risk of accidents.

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