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Despite the high frequency and serious consequences of protein–energy malnutrition, prevention and treatment of malnutrition do not currently receive appropriate attention. Increased awareness of the importance of nutritional screening among older people is needed. The overall aim of this thesis was to extend our current knowledge about malnutrition and the consequences of a poor nutritional status in relation to preterm death, and to identify possible risk factors for developing malnutrition among older people. The aim of Paper I was to estimate the prevalence of malnutrition and to examine the associations between mealtime habits, meal provision, and malnutrition among older people admitted to a Swedish hospital. The aim of Paper II was to examine whether nutritional status, defined according to the three categories in the full Mini Nutritional Assessment (MNA) instrument, is an independent predictor of preterm death in older people.

The baseline survey was a cross-sectional study of 1771 patients aged ³65 years who were admitted to hospital. Nutritional status was assessed using the MNA instrument, and possible risk factors associated with malnutrition were recorded during the hospital stay (Paper I). Overall survival was followed up after 35–50 months in a cohort study of 1767 participants (Paper II).

Of the 1771 participants, 35.5% were well-nourished, 55.1% were at risk of malnutrition, and 9.4% were malnourished at baseline. An overnight fast >11 hours was associated with risk of malnutrition (odds ratio (OR) 1.46; 95% confidence interval (CI) 1.14–1.87) and being malnourished (OR 1.67; 95% CI 1.04–2.69). Fewer than four eating episodes a day was associated with both risk of malnutrition (OR 1.88, 95% CI 1.52–2.32) and being malnourished (OR 3.10; 95% CI 2.14–4.49). Not cooking independently was also associated with both risk of malnutrition (OR 1.9; 95% CI 1.30–2.93) and being malnourished (OR 5.04; 95% CI 2.95–8.61). At the 50-month follow-up, the survival rates were 75.2% for well-nourished participants, 60.0% for those at risk of malnutrition, and 33.7% for malnourished participants. After adjusting for confounders, the hazard ratios (95% CI) for all-cause mortality were 1.56 (1.18–2.07) in the group at risk of malnutrition and 3.71 (2.28–6.04) in the malnourished group. Nutritional status defined according to the three categories in the full MNA independently predicted preterm death in people aged 65 years and older.

This thesis provides additional knowledge of the current nutritional situation among older people admitted to hospital. The high prevalence and serious consequences of malnutrition demonstrated in this thesis underline the importance of screening and taking actions to counteract malnutrition among older people. The data showing that the length of overnight fasting and number of eating episodes per day are possible risk factors for malnutrition are consistent with the current nutritional recommendations. This knowledge may stimulate care providers to decrease the length of overnight fasting and increase the number of eating episodes per day among older people at risk of malnutrition.

Aims The overall aim of this thesis was to extend current knowledge about the prevalence of malnutrition, to identify possible risk factors for development of malnutrition, and to describe the consequences of malnutrition in relation to all-cause and cause-specific mortality among older adults admitted to hospital.

Methods The prevalence of malnutrition was estimated in a cohort of 1771 older adults (≥65 years) who were admitted to a Swedish hospital during 2008–2009 (15 months) and screened for malnutrition using the Mini Nutritional Assessment (MNA) instrument. Possible risk factors for malnutrition were recorded during the hospital stay (Study I). Dietary intake 10 years earlier (in 1997) was collected for 725 of these older adults (Study II). All-cause (Study III) and cause-specific (Study IV) mortality were followed up after medians of 3.5 and 5.1 years, respectively, for 1767 of the participants.

Results The prevalence of malnutrition was 9.4% while 55.1% were at risk of malnutrition. Risk factors for malnutrition was an overnight fast >11 hours, <4 eating episodes a day, and not cooking independently. In middle-aged and older adults with a body mass index <25 kg/m² in 1997, the risk of malnutrition increased for each additional percentage point of energy from total, saturated and monounsaturated fat at follow-up after 10 years. Malnourished older adults had almost four times higher risk of death during follow-up, while those at risk of malnutrition had a 56% higher risk, compared to well-nourished. Furthermore, well-nourished older adults had consistently lower risk of death, regardless of the cause of death.

Conclusions Only 35.5% of older adults admitted to hospital were well-nourished. The identified risk factors could be used in interventions aimed at preventing malnutrition. Normal-weight and underweight middle-aged and older adults should consider limiting the intake of total fat and/or improve the quality of the fat in the diet in order to decrease the risk of becoming malnourished later in life. Malnutrition and risk of malnutrition were associated with increased overall and cause-specific mortality. These relationships emphasize the need for nutritional screening to identify individuals who may require nutritional support in order to avoid preterm death.