Want to stay away from osteoporosis? Then, start playing basketball or volleyball regularly, as these load-bearing sports can help prevent the bone disease, scientists say. Researchers at University of Gothenburg in Sweden found that four hours a week or more of such sports, played by men during their 20s, increases bone mass and might provide some protection from developing osteoporosis later in life. "Men who increased their load-bearing activity from age 19 to 24 not only developed more bone, but also had larger bones compared to men who were sedentary during the same period," study author Mattias Lorentzon was quoted as saying by LiveScience. Osteoporosis, which affects more than 200 million people worldwide, casuses bones to become thinner and less dense. Bigger bones with more mass are thought to offer a shield against osteoporosis, a disease that affects men and women alike, in which bones become porous and weak over time and start to fracture by age 50 or later. "Osteoporosis actually seems to get its start by age 25 when bones start to lose tissue. So this study sends an important message to young men," Lorentzon said. "The more you move, the more bone you build." Past studies have suggested that load-bearing physical activity might shield men and women from bone loss, which occurs as part of the aging process. To find out whether the link would hold true in a very large study, Lorentzon and his team evaluated 833 men aged between 18 and 20 years. The researchers measured the participants` bone mass and collected information about their exercise habits. They came back to the lab to report activity levels and get bone scans again after five years. The findings, published in the Journal of Bone and Mineral Research, showed that men who both started off with a high level of load-bearing exercise at the study`s start and those who stepped up the pace had a better chance at building bone than men who remained sedentary or those who slacked off during the five year period. The researchers also found that for every hour of extra physical activity during the five year period, the men in this study gained bone mass. And those who engaged in load-bearing sports for four hours a week or more showed an increase in hip bone density of 1.3 per cent. At the same time, men who remained sedentary during the period lost about 2.1 per cent of bone mass in the hip, a worrisome finding because thinning hip bones are more likely to break later in life. Hip fractures in men often lead to serious disability and complications, including life-threatening post-surgery infections and cardiovascular events. This study was conducted in white men recruited mostly from the city of Gothenburg in Sweden. However, Lorentzon noted the findings likely apply to Caucasian men in the US and in other countries. But additional research should be done to show that such load-bearing exercise can protect men in other ethnic groups and women, he added.