| 
      
        | Groups | Months | Mild (NO:36)
 Mean ± S.D.
 | Moderate (NO:62)
 Mean ± S.D.
 | Severe (NO:42)
 Mean ± S.D.
 |  
        | M1 | 10.18 ± 0.26  BC | 8.59 ± 0.45 AC | 6.54 ± 0.39 AB |  
        | M2 | 10.57 ± 0.59 ** BC | 9.35 ± 0.44 ** AC | 8.14 ± 0.91 ** AB |  
        | M3 | 10.91 ± 0.48 ** BC | 9.91 ± 0.57 ** AC | 8.84 ± 1.03 ** AB |  
        | M4 | 11.45 ± 0.53 ** BC | 10.56 ± 0.63 ** AC | 9.48 ± 0.98 ** AB |  
        | M5 | 12.00 ± 0.53 ** BC | 11.09 ± 0.74 ** AC | 10.19 ± 0.88 ** AB |  
        | M6 | 12.56 ± 0.48 ** BC | 11.67 ± 0.78 ** AC | 10.89 ± 0.88 ** AB |  
        | M7 | 13.29 ± 0.65 ** BC | 12.23 ± 0.77 ** AC | 11.58 ± 0.93 ** AB |  |