TABLE 1

Risk factors/predisposing factors for nontuberculous mycobacterial pulmonary disease

Risk factorExamples
Exposure
 DomesticHousehold plumbing fixtures
Showerheads
Taps
Humidifiers
Heating/ventilation systems
Homelessness, incarceration or institutionalisation
 OccupationalMining
Healthcare
Steel industry
Farming and breeding
Veterinary
Waste collection
Fish farming
Geology and speleology
 RecreationalGardening
Camping
Horse-riding
Fishing
Swimming
Hot tubs
Damage substrate
 Pre-existing lung diseaseCF
Non-CF bronchiectasis
Primary ciliary dyskinesia
Previous pulmonary tuberculosis
Asthma
COPD
Alpha-1 antitrypsin deficiency
Pneumoconiosis (especially silicosis)
ILDs (especially pulmonary alveolar proteinosis)
ABPA
Williams–Campbell syndrome
Congenital tracheobronchomegaly (Mounier–Kuhn syndrome)
 Demographic and constitutional factors  (Lady Windermere syndrome)Older age (>40–70 years)
Female sex
Non-smoking history
Slender body habitus
Low BMI/low body fat
Scoliosis
Pectus excavatum
Flattened thoracic cage (platythorax)
“Straight back syndrome”
Low vitamin D
GORD
Defective immunity
 Primary immunodeficiencyMutations in the IFN-γ/IL-12 pathway (e.g. IFNγ-R1, IFN-γ-R2, IL-12R, STAT, tyrosine kinase 2)
Deficiency in NF-κB essential modulator
Defective macrophage and dendritic cell function (e.g. chronic granulomatous disease)
Defective T-cells (e.g. CVID, SCID)
Complement C4 deficiency
 Acquired immunodeficiencyHIV-AIDS
Acquired neutralising anti-IFN-γ antibodies
Diabetes mellitus
Chronic kidney disease
Malignancy
Alcohol abuse
 MedicationsOral corticosteroids
Inhaled corticosteroids
TNF-α antagonists
Solid organ transplantation (particularly lung transplant)
Haematopoietic stem cell transplantation
Cancer chemotherapy

CF: cystic fibrosis; COPD: chronic obstructive pulmonary disease; ILD: interstitial lung disease; ABPA: allergic bronchopulmonary aspergillosis; BMI: body mass index; GORD: gastro-oesophageal reflux disease; IFN: interferon; IL: interleukin; STAT: signal transducer and activator of transcription 1; CVID: common variable immunodeficiency; SCID: severe combined immune deficiency; TNF: tumour necrosis factor.