Disease activity and risk of lymphoma in patients with rheumatoid arthritis: nested case-control study

maxilla that might predispose to retropalatal upper airway narrowing.Since facial structure is at least partly inherited, this may provide the familial link in the sudden infant death syndrome, although larger studies are required to confirm these findings.These results also provide a further link between the sudden infant death and obstructive sleep apnoea/hypopnoea syndromes, as the facial changes are similar in both conditions.Our study indicates that a retrognathic facial structure should be considered as an additional risk factor for the sudden infant death syndrome, and the suggested mechanism for upper airway narrowing could also contribute to the posture dependence of the syndrome and to the association with upper respiratory tract infections, which predispose to obstructive apnoeas by increasing nasal resistance.We suggest there is a need to assess whether prevention of obstructive apnoeas, such as by continuous positive airway pressure, prevents the sudden infant death syndrome in high risk infants.