The Relationship between Land Use and Travel Patterns: Variations by Household Type

In this chapter we address the following question: Does the direction and/or magnitude of the influence of urban form on travel vary across different household types? If the answer is `yes', we can suggest the existence of interaction effects in the impact of urban form. If, on the other hand, the analysis shows no differences in the impact of urban form, this suggests that household types display similar responses to urban form, irrespective of their personal situation. In particular, we investigate differences in the effect of urban form, or residential context, on trip frequency and travel time across six household types: single workers, two- and one-worker couples, two- and one-worker families and senior households. The analysis of travel time is segmented by trip purpose: we differentiate between commuting times, `maintenance' times (e.g. trips running household errands, moving goods, shopping, giving lifts to people etc.) and leisure travel times, for several reasons. First, this broader perspective permits us to obtain better insights into the impact of urban form on travel patterns than a focus on commuting alone. Second, the number of both maintenance and leisure trips is larger than that ofcommuting trips in the Netherlands (Schwanen et al., 2001a). The data used for this analysis is derived from a nationally representative sample of the Dutch population, and stems from the 2001 Netherlands National Travel Surve

Diabetes, but not hypertension and obesity, is associated with postoperative cognitive dysfunction

BACKGROUND/AIMS: Older people undergoing surgery are at risk of developing postoperative cognitive dysfunction (POCD), but little is known of risk factors predisposing patients to POCD. Our objective was to estimate the risk of POCD associated with exposure to preoperative diabetes, hypertension, and obesity. METHODS: Original data from 3 randomised controlled trials (OCTOPUS, DECS, SuDoCo) were obtained for secondary analysis on diabetes, hypertension, baseline blood pressure, obesity (BMI ≥30 kg/m(2)), and BMI as risk factors for POCD in multiple logistic regression models. Risk estimates were pooled across the 3 studies. RESULTS: Analyses totalled 1,034 patients. POCD occurred in 5.2% of patients in DECS, in 9.4% in SuDoCo, and in 32.1% of patients in OCTOPUS. After adjustment for age, sex, surgery type, randomisation, obesity, and hypertension, diabetes was associated with a 1.84-fold increased risk of POCD (OR 1.84; 95% CI 1.14, 2.97; p = 0.01). Obesity, BMI, hypertension, and baseline blood pressure were each not associated with POCD in fully adjusted models (all p > 0.05). CONCLUSION: Diabetes, but not obesity or hypertension, is associated with increased POCD risk. Consideration of diabetes status may be helpful for risk assessment of surgical patients