In each BLE connection event you can send up 20 bytes of data. A 32 bit value will consume 4 of those bytes. There are a few methods for breaking up 32 bit integer into four 8 bit values that utilize bit-wise operations, pointers, etc. This part is completely up to your discretion. Once broken up, the simplified way of loading them into your GATT db is to load them one by one:
db_pdu.pdu = byte_one;
db_pdu.pdu = byte_two;
db_pdu.pdu = byte_three;
db_pdu.pdu = byte_four;
This can be run in a loop with the code that breaks apart the 32-bit value, but I split it up here for understanding.
Alternatively, you can take a look at the wiced_sense app which uses a method of incrementation to the GATT db which is highly efficient.
Lastly, do not rule out scaling to maximize the amount of data you can send, or to minimize power consumption. If you don't require the highest degree of accuracy in your application, go ahead and divide the value by 10, send it, and multiply it back out on the other side. This may save you one or two bytes.