cant fetch SQLite column

Im trying to fetch a column of senderId's from my messages table and then store them in an array. However my while loop is not functioning correctly:

('senderIds' is an NSMutableArray declared in the header file.)

-(void)fetchsenderIds {

const char *dbpath = [_databasePath UTF8String];
sqlite3_stmt    *statement;

if (sqlite3_open(dbpath, &_messagesDB) == SQLITE_OK)
{
    NSString *querySQL = [NSString stringWithFormat:
                          @"SELECT senderId FROM messages"];

    const char *query_stmt = [querySQL UTF8String];

    if (sqlite3_prepare_v2(_messagesDB,
                           query_stmt, -1, &statement, NULL) == SQLITE_OK)
    {

        //Loop through the results and add them to the array
        while(sqlite3_step(statement) == SQLITE_ROW)
        {

            // Init the Data Dictionary
            NSMutableDictionary *dataDictionary2=[[NSMutableDictionary alloc] init];
            NSString *recordModified = [[NSString alloc] initWithUTF8String:(const char *)sqlite3_column_text(statement, 0)];
            [dataDictionary2 setObject:[NSString stringWithFormat:@"%@", recordModified] forKey:@"senderId"];
            [self.senderIds addObject: dataDictionary2];



            NSLog(@"self.senderIds = %@", self.senderIds);



        }
        sqlite3_finalize(statement);
    }
    sqlite3_close(_messagesDB);
}
}