An analysis of dietary supplement utilisation, nutritional risk, and physical activity patterns in older Australians

Sonya Brownie

Little research has been undertaken to define the prevalence and patterns of dietary supplement use among older Australians and the characteristics of older Australian supplement users. This study sought to obtain information about the use of dietary supplements by Australians aged 65 years and over. The primary objective of this study was to use these data to construct a demographic and health profile of older Australian supplement users. The secondary objective was to assess the extent of nutritional risk, according to the Australian Nutrition Screening Initiative checklist, and to identify risk factors associated with poor nutritional status in older Australians. In 2000, the Australian Electoral Commission provided names, address, gender and five-year age-range information for all Australians aged 65 years and over. In January 2001 a letter outlining the nature of the investigation and inviting participation was posted to 2,457 randomly selected older Australians nationwide. A reminder-to complete card was posted to all participants four weeks after the original letter had been mailed. Each respondent received the initial letter, questionnaire, follow-up card and pre-paid envelope in which to return the completed survey. Responses were obtained from 1,263 predominantly independently living Australians aged 65 years and over. This represents a response rate of 62% after adjusting for non-deliveries. The 12-page questionnaire was designed to obtain information about the health and lifestyle practices of older Australians, including their use of dietary and health supplements. The development of the instrument involved two in-depth focus groups and survey pre-testing by residents in an aged care facility and independently living individuals aged 65 years and over. In total 70 participants contributed to the construction and modification of the instrument. Men (n=641) were aged 65-98 years with a mean age of 73 years (SD 6.21). Women (n=622) were aged 65-95 years with a mean age of 74 years (SD 6.76). The majority of the sample were living with their partner only (61 %), were born in Australia (73%), had some secondary school education (43%), reported an income of less than $19,000 per annum, and rated their health as very-good to excellent (77%). At the time of survey, 43% reported the use of at least one dietary and health supplement: more than half the women (52%) and over a third of the men (35%) reported using these products. The supplements used most often were vitamin C, multivitamin/mineral preparations, fish oils, vitamin E, calcium, garlic capsules or oil, vitamin B (single or mixed), other single vitamins or minerals, zinc and Gingko. Supplement use was significantly related to several demographic and lifestyle features including gender, educational level, smoking status and number of visits to complementary health therapists. Supplement users appeared to rely on their doctor, newspapers, friends or family, and pharmacy staff for information about supplements. The most commonly cited reasons for supplement use were to enhance energy levels, improve stamina and promote feelings of wellness. This study revealed some distinct differences in the health profile of supplement users compared to non-supplement users. For example, supplement users experienced significantly more symptoms and consumed more medication than non-supplement users. Furthermore, individuals with chronic musculoskeletal ailments such as arthritis, osteoporosis and generalised back or neck problems were significantly more likely to report the use of supplements than those without these conditions. In contrast, a diagnosis of hypertension or a heart condition were significant barriers to supplement use. The extent of supplement usage by this older sample reflects their high level of interest in self-care and health maintenance, however some aspects of this behaviour raised concerns. Only half the supplement users (often-to-always) informed their doctor about the products they used; yet the majority of supplements were consumed regularly (daily or every few days) and for an extended period (more than three years). The most common potential drug-supplement interaction was between calcium supplements and anti-hypertensives. In general, the types of products consumed were not those that have been shown to specifically benefit older people. Evidence suggests that nutrients such as folate, vitamin B 12, calcium and vitamin D can moderate the rate of cognitive and functional decline in the older person. With the exception of calcium, very few supplement users consumed preparations providing these nutrients. The Australian Nutrition Screening Initiative checklist identified 41% of the sample at low nutritional risk, 23% at moderate nutritional risk and 36% at high nutritional risk. The most frequently occurring risk factors in the study population were: taking three or more different prescription or over-the-counter drugs (44%); having an illness that led to changes to the kind and/or amount of food consumed (34%); eating alone most of the time (28%); not eating dairy products most days (18%); consuming three or more alcoholic beverages each day (18%); and unintentional weight change of 5kg in the last six months (15% ). Approximately 9% did not eat three meals per day, 5% did not eat fruit or vegetables most days and 5% reported having insufficient funds to buy food. Ageing was associated with an increase in the prevalence of several risk factors and in the number of risk factors reported. Poor food consumption patterns were associated with: insufficient fluid intake; impediments to shopping, cooking and self-feeding; and financial restrictions. Individuals who reportedly ate fewer than three meals a day were more likely to experience oral health problems, swallowing difficulties or to be eating alone. When risk factors were recoded to the original US instrument item weights, the Australian checklist identified almost twice the number of people at high nutritional risk compared to an estimate using the NSI checklist. In 2004, semi-structured interviews (n=35) were conducted to explore how older people interpret, and respond to, the ANSI checklist. The scores derived from the ANSI checklist were compared to scores derived from using a food variety checklist. The ANSI identified that more than half (54%) of the interview participants were at nutritional risk, yet the food variety checklist showed that the majority of them (94%) had good to very-good food variety scores. These interviews revealed that many individuals found the ANSI statements ambiguous and confusing, resulting in a high proportion of inaccurate and invalid responses. Perceived poor health, chronic disease, lack of motivation and energy, were barriers to achieving regular exercise. Men participated in a wider range of physical activities and were more likely to average at least 30 minutes of activity most days compared to women. Living arrangements, ethnicity, education and income were important sociological determinants of low, medium, and high levels of physical activity. Participation rates in activities that are particularly beneficial to the older person, such as Tai chi exercises or weight resistance training, were low. This study has shown that the current patterns of dietary supplement use and physical activity among older Australians is inadequate to reduce the morbidity associated with chronic health conditions such as arthritis, osteoporosis, and neurological impairments. It appears that older supplement users could benefit from education about the importance of achieving optimal nutrient intakes and regular exercise to maintain functional independence and quality of life. Future investigations should focus on developing reliable instruments for obtaining information about the use complementary medicines in the older population, the total intake of calcium from dietary and supplemental sources, and the risk factors that contribute to poor nutritional status in this age group.

An analysis of dietary supplement utilisation, nutritional risk, and physical activity patterns in older Australians

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An analysis of dietary supplement utilisation, nutritional risk, and physical activity patterns in older Australians

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