Creatinine levels relate to both muscle mass and to kidney function. As you age, your muscle mass decreases but your kidneys tend to function less effectively. The net result is not much change in creatinine levels in the blood as you get older.
As a result, California employers are required by law to have workers' compensation insurance, even if they have only one employee. And, if your employees get hurt or sick because of work, you are required to pay for workers' compensation benefits.
The State of California requires all employees to pay into its short-term disability insurance (SDI) program through payroll deductions. When employees become unable to work due to disability, they can collect weekly benefits from the program until they are either ready to go back to work or the benefits expire.