A WHtR of over 0.5 is critical and signifies an increased risk; a 2010 systematic review of published studies concluded that "WHtR may be advantageous because it avoids the need for age-, sex- and ethnic-specific boundary values".[5] For people under 40 the critical value is 0.5, for people aged 40–50 the critical value is between 0.5 and 0.6, and for people over 50 the critical values start at 0.6.[6]