The Occupational Safety and Health Administration yesterday issued revisions to the seven-year-old regulation that protects more than 170,000 workers in textile and other industries from effects of cotton dust, such as brown lung disease.

The revisions stem largely from the Reagan administration's commitment to deregulation but are based on an agreement between the Amalgamated Clothing and Textile Workers Union and the American Textile Manufacturers Institute.

Labor Secretary William E. Brock said the changes "guarantee the continuation of the necessary protections" but will "make the standard more cost-effective and performance-oriented."

The revisions reduce some worker-protection requirements. In work areas where cotton dust levels are consistently low, medical examinations for employes now will be required every two years instead of annually.

In low-dust workplaces, monitoring of dust levels now will be required once a year. The previous twice-a-year requirement will continue in areas with high dust levels.

Another revision eliminates regulation in the knitting industry, where studies indicate the work force will remain healthy without a federal standard.

The new standard maintains the current maximum allowable exposure limits and requirements for engineering controls, education and training established in 1978 for the textile industry.