A pineapple pesticide linked to milk in Hawaii also has a connection with men’s brains, and those men may develop Parkinson's disease, according to a new study published in journal Neuron.

The study has made its place in a long list of studies that have linked various pesticides to the degenerative disorder of the central nervous system that mainly affects the motor system. The new findings have also supported an observation stating that individuals who smoke are safe against Parkinson's disease.

The study by Dr. Robert Abbott, a researcher from the Shiga University of Medical Science, and some colleagues included more than 400 Japanese-American men from Hawaii in the study. The subjects were part of a larger study of aging. The subjects were asked about their milk drinking habits. They not only reported how much milk they drank, but also donated their brains after they died.

Study researchers explained that participants who drank over 16 ounces of milk every day had the fewest cells the substantia nigra. The researchers also searched for the pesticide heptachlor that was taken off the market in the US in 1988. About 90% participants who drank the most milk had heptachlor epoxide, while just 63% subjects who didn’t consume milk were with heptachlor epoxide, as per the researchers.

The Parkinson's Disease Foundation said, “The researchers could not test whether the milk the men drank was contaminated with pesticides (heptachlor, in this case), and no one knows how long or how widespread the contamination was before being detected”.