▁ 9 6 8 9 ▁subjects . ▁ ▁P ock ets ▁> ▁ 5 mm ▁were ▁found ▁in ▁ 7 . 6 % ▁of ▁non - H is pan ic ▁white ▁subjects , ▁ 1 8 . 4 % ▁of ▁non - H is pan ic ▁black ▁subjects ▁and ▁ 1 4 . 4 % ▁in ▁Mexican ▁Americans ; ▁a ▁total ▁of ▁ 8 . 9 % ▁of ▁all ▁subjects ▁had ▁po ckets ▁> ▁ 5 mm . ▁ ▁Att achment ▁loss ▁> ▁ 5 mm ▁was ▁found ▁in ▁ 1 9 . 9 % ▁of ▁non - H is pan ic ▁white ▁subjects , ▁ 2 7 . 9 % ▁of ▁non - H is pan ic ▁black ▁subjects ▁and ▁ 2 8 . 3 % ▁of ▁Mexican ▁Americans ; ▁a ▁total ▁of ▁ 1 9 . 9 % ▁of ▁all ▁subjects ▁had ▁attachment ▁loss ▁> ▁ 5 mm . ▁ ▁This ▁suggests ▁that ▁severe ▁period ont itis ▁in ▁not ▁uniformly ▁distributed ▁among ▁various ▁races , ▁eth nic ities ▁and ▁so cio e conom ic ▁groups . ▁ ▁H ug os on ▁( 1 9 9 8 ) ▁exam ined ▁three ▁random ▁samples ▁of ▁ 6 0 0 , ▁ 5 9 7 ▁and ▁ 5 8 4 ▁subjects ▁in ▁ 1 9 7 3 , ▁ 1 9 8 3 ▁and ▁ 1 9 9 3 ▁respectively . ▁ ▁These ▁subjects ▁were ▁aged ▁ 2 0 – 7 0 ▁years . ▁ ▁The ▁sever ity ▁of ▁disease ▁was ▁divided ▁into ▁five