New York, Jan 14 (IANS) Despite its harmful effects, the use of hookah has increased in the US and is being promoted through Instagram, a study has found.The study conducted by researchers from the University of Southern California (USC) noted that as cigarette use declined between 2005 and 2015 in the US, hookah use has increased.According to the study, Instagram's focus on images facilitates picture-based advertising where hookah lounges promote drink specials at the same time nightclubs promote hookah specials."Instagram users may see pictures of their friends and family enjoying themselves in social settings where hookah use is a focus," said Tess Boley Cruz, professor at USC.The researchers analysed more than 5,000 posts on Instagram between February 19 and May 19, 2016, by combining the hashtag 'hookah'.The study noted that more than a third were promotional material for hookah lounges, restaurants, bars and nightclubs, while a quarter depicted people lounging and using a hookah. "Hookah promotion on social media was not surprising. However, a third of the images showcased or referenced alcohol, suggesting nightlife entertainment regularly depicts and promotes using multiple substances -- a clear justification for a public health response," said Jennifer Unger, professor at USC, in a study published in the journal Nicotine and Tobacco Research. However, researchers did not find promotional material discouraging hookah use in their data. The study stressed that it would be important for tobacco control researchers to develop programmes to combat the positive imagery, and potential normalisation, of hookah use on Instagram.