I used the following code to download and explore my data set, however I do not see the "Age" data for my samples in any of the clinical data columns, even when I examine the clinical data columns, such as "description":

    gdat <- getGEO('GSE52401', 
                   GSEMatrix=TRUE,
                   getGPL=FALSE)

    gse <- gdat$GSE52401_series_matrix.txt.gz
    mdat <- exprs(gse)

    clindat <- pData(gse)

colnames(clindat)
# [1] "title"                   "geo_accession"           "status"                  "submission_date"        
# [5] "last_update_date"        "type"                    "channel_count"           "source_name_ch1"        
# [9] "organism_ch1"            "characteristics_ch1"     "characteristics_ch1.1"   "characteristics_ch1.2"  
# [13] "molecule_ch1"            "extract_protocol_ch1"    "label_ch1"               "label_protocol_ch1"     
# [17] "taxid_ch1"               "hyb_protocol"            "scan_protocol"           "description"            
# [21] "description.1"           "data_processing"         "platform_id"             "contact_name"           
# [25] "contact_email"           "contact_phone"           "contact_institute"       "contact_address"        
# [29] "contact_city"            "contact_state"           "contact_zip/postal_code" "contact_country"        
# [33] "supplementary_file"      "data_row_count"          "disease state:ch1"       "gender:ch1"             
# [37] "sample type:ch1" 

Am I missing something? My apologies if this is obvious, it is my first time looking at GEO data.