"CREATE TABLE IF NOT EXISTS user (
id INTEGER not null primary key,
area CHAR(6),
age INTEGER not null,
active INTEGER not null)"
Depending on the id value, its storage might be around 7 bytes.
Assuming ages are in 0 to 127, and active values are 0 or 1 the SQLite storage for those is two or three bytes (1 byte per column "overhead", and another byte holds age when it is more than 1)
You are probably looking at around 17 bytes per row if length(area) is typically 6 bytes (look at your database disk size after you've inserted a million records to see if I'm right).
You could probably save 2 bytes per row by using a BLOB to hold all of the non-key information. The blob could hold age and active in a single byte, and its remaining bytes would hold area.
CREATE TABLE IF NOT EXISTS user (id INTEGER PRIMARY KEY, info BLOB);
You could create a VIEW that extracts value in your preferred multi-column form (and the VIEW could have triggers that support inserts and updates in the multi-column form, but those triggers would probably not be as fast as building the BLOB in your application).
Saving 2 bytes out of 17 might give you a 10% or more speed boost.