Background Although certain types of sedentary behaviour have been linked to metabolic risk, prospective studies describing the links between sitting with incident diabetes are scarce and often do not account for baseline adiposity. We investigate the associations between context-specific sitting and incident diabetes in a cohort of mid-aged to older British civil servants.

Methods Using data from the Whitehall II study (n=4811), Cox proportional hazards models (adjusted for age, sex, ethnicity, employment grade, smoking, alcohol intake, fruit and vegetable consumption, self-rated health, physical functioning, walking and moderate-to-vigorous physical activity, and body mass index (BMI)) were fitted to examine associations between total sitting and context–specific sitting time (work, television (TV), non-TV leisure time sitting at home) at phase 5 (1997–1999) and fasting glucose-defined incident diabetes up to 2011.

Results Total sitting (HR of the top compared with the bottom group: 1.26; 95% CI 1.00 to 1.62; p=0.01) and TV sitting (1.33; 95% CI 1.03 to 1.88; p=0.05) showed associations with incident diabetes; once BMI was included in the model these associations were attenuated for both total sitting (1.19; 95% CI 0.92 to 1.55; p=0.22) and TV sitting (1.31; 95% CI 0.96 to 1.76; p=0.14).

Conclusion We found limited evidence linking sitting and incident diabetes over 13 years in this occupational cohort of civil servants.