The phrase "a more common cause" is correct and usable in written English.
You can use it when discussing reasons or factors that are frequently encountered or observed in a particular context.
Example: "While there are many potential explanations for the issue, a more common cause is often overlooked."
Alternatives: "a more frequent reason" or "a more typical factor".
But as people age, reaching up and back, known as extension, becomes a more common cause.
Occult vascular malformations of the optic nerve and chiasm may be a more common cause of visual deterioration than previously recognized.
Even the famines that sometimes ravage less-developed countries are rarely due to overpopulation--civil war is a more common cause.
While untreated diabetes itself can be deadly, complications from the disease such as heart attacks are a more common cause of death.
While heredity can play a role in the development of bunions — for example, you may have been born with flat feet or low arches — a more common cause is frequent wearing of shoes with a pointed forefoot that squeezes your toes, or high heels that force your toes too far forward in the shoes.
We conclude that although drug related new-onset seizures are not a common cause of seizures overall, bupropion might be a more common cause of drug related new-onset generalized seizures presenting to the Emergency Department than previously thought, occurring in more than one-fifth of this subgroup of cases.
Available information suggests that with control of corneal blindness from vitamin A deficiency and measles, cataract in children is becoming a relatively more common cause of blindness [ 26].
Spiders are a far more common cause of serious injury.
Open-flame illumination, however, was a much more common cause of explosions until the introduction of the Davy safety lamp (about 1815), in which the flame is enclosed in a double layer of wire gauze that prevents ignition of flammable gases in the air of the mine.
The new standard abandons the open flame test, and instead requires that upholstered furniture resist ignition from smoldering objects on the surface, a much more common cause of fires.
Stroke currently is a far more common cause of death in China than is CHD.
