Moore et al. BMC Public Health 2010, 10:612 http://www.biomedcentral.com/1471-2458/10/612 Page 4 of 6 Figure 2 Rates of M. avium-intracellulare reports by age group (years), England, Wales and Northern Ireland, 1995-2006. mentioned in 30% (109), 21% (75), 11% (39) and 5% (18) of reports respectively. M. malmoense M. malmoense was the second most commonly reported species over the study period (Table 1). The rate of reports was stable at between 0.2 and 0.3 per 100,000 (Figure 1), a mean of 126 per year. The majority of reports were in men (939/1488, 63%) and in people aged 45 years and over (1255/1480, 85%); just 5% (77) occurred in young adults aged 15-44 years and 10% (148) were in those under 15 years. Ninety percent (1266/1404) of infections were from pulmonary sites. Where information was available in clinical comments (5%, 73/1510), chronic respiratory illness was most com- monly reported (24, 33%), followed by cancer (4, 5%). M. kansasii The rate of M. kansasii reports rose from 0.1 per 100,000 in 1995 to 0.3 per 100,000 in 2005 (Table 1, Figure 1). Increases were seen in both sexes, but mainly in those aged 45 and over. Ninety-two percent (1282/ 1389) of reports were from a pulmonary site. Chronic respiratory illness was again the most commonly reported clinical comment (20/69, 29%) where informa- tion was available (69/1380, 5%). M. gordonae Reports of M. gordonae increased from just 1 in 1995 to 153 in 2006, when it was the second most commonly reported species and at a rate of 0.3 per 100,000 population (Table 1, Figure 1). In contrast to the trends seen by region for all NTM, reports were most commonly from Yorkshire and the Humber (133/516, 26%), with just 0.4% (2/516) coming from the North East. Sixty-one per- cent of reports were in males (307/505). Although the increase was largest in those over 65 years old (rising to 0.8 per 100,000 in 2006) and in pulmonary sites, numbers increased in both sexes, across all age groups and in both pulmonary and extra-pulmonary infections. Where clinical comments were present (41/516, 8%), 49% (20/41) men- tioned chronic respiratory illnesses. Discussion Main findings The number and rate of NTM reports increased consid- erably between 1995 and 2006, continuing the trend reported previously [11]. Increases were seen across many species reported, but were most noticeable in M. avium-intracellulare and M. gordonae. The rise in all NTM was predominantly in pulmonary sites in those over 60 years of age. Sixty percent of all NTM reports were in men and rates were consistently higher in men across all years. Men may be more susceptible to NTM infection due to higher historical rates of smoking and COPD. A higher index of suspicion of tuberculosis in men, and therefore an increased submission of investigative samples from men, may also have contributed to this finding if NTM were found as a consequence. Previous increases in M. avium-intracellulare infec- tions have been linked to increases in HIV/AIDS [6].