my $up = "UPDATE Prior_to_CI_calc_A_$region 
            SET SUM_wi           = $SUM_Weight_wi, 
                Sum_wixi_x_1000  = $SUM_wixi_x_1000_fill, 
                Sum_wi2xi_x_1000 = $SUM_wi2xi_x_1000_fill
            FROM Prior_to_CI_calc_A_$region A 
            WHERE     A.Aggregated_area LIKE '$Aggregated_area_fill' 
                  AND A.Cause LIKE '$Cause_fill'
";

##</code><code>##

  sub update_region {
    my ($region) = @_;
    my $table  = "Prior_to_CI_calc_A_$region";
    sprintf "UPDATE %s 
            SET SUM_wi           = ? ,
                Sum_wixi_x_1000  = ? , 
                Sum_wi2xi_x_1000 = ?
            FROM %s A 
            WHERE     A.Aggregated_area LIKE ? 
                  AND A.Cause           LIKE ?
", $table, $table;
  };

  my $region = "foo";
  my $query = $dbh->prepare(update_region($region));

  $query->execute(1,2,3,'US','unknown');