You say loop .. so if you want to do this for a dir instead of the current document;
Dim sFile As Variant
Dim oShell: Set oShell = CreateObject("Shell.Application")
Dim oDir: Set oDir = oShell.Namespace("c:\foo")
For Each sFile In oDir.Items
Debug.Print oDir.GetDetailsOf(sFile, XXX)
Next
Where XXX is an attribute column index, 9 for Author for example. To list available indexes for your reference you can replace the for loop with;
for i = 0 To 40
debug.? i, oDir.GetDetailsOf(oDir.Items, i)
Next
Quickly for a single file/attribute:
Const PROP_COMPUTER As Long = 56
With CreateObject("Shell.Application").Namespace("C:\HOSTDIRECTORY")
MsgBox .GetDetailsOf(.Items.Item("FILE.NAME"), PROP_COMPUTER)
End With