Support staff rather than teachers make up most of those off with long term illness in Birmingham schools, according to the local authority.
Education chiefs have provided more detail on the make-up of the 302 school staff who have been off for 14 weeks or more.
The figure, highlighted by The Birmingham Post earlier this month, represented a rise of almost a third on the previous year when there were 210 school workers off due to long term sickness.
Teachers made up 103 of the current total, Birmingham City Council revealed - a one per cent rise on last year.
School support staff such as dinner supervisors, classroom assistants and administrative workers, represented the biggest bulk of long term illness.
"The main reasons for teaching staff on long term sick leave include waiting for operations and people who have had an accident," said a spokesman.
"We have 17 cases of hospitalisation of teachers and support staff.
"We have 59 lunchtime supervisors off long term sick which is an increase on last year and may be attributable to age.
"The illnesses include terminal illness, depression and hospitalisation for various conditions."
The authority said it was working with schools and advising them how to progress long term cases. Measures included referring unwell workers to occupational health specialists before they became more seriously ill.
"We advise schools how to use the occupational health service to help make assessments of individuals' ability to return to work and also to provide counselling services in cases of stress, anxiety and depression," said the spokesman.
Teaching union leaders blamed the pressure of Ofsted inspections, the Government's results-driven agenda, initiative-fatigue and loss of teacher autonomy for piling on the stress in schools.
But the Department for Education and Skills maintains reforms have lessened the burden on teachers.