Previous research has shown that Australian women are at risk of substantial weight gain in young adulthood and in mid-age, and that dietary factors are likely to play an important role in this weight gain. But little data are available on how dietary patterns vary according to age, key socio-demographic or behavioural factors and hence there is a need for evidence to support nutrition programs or policies.

The aims of this study were to assess the major dietary patterns of two age cohorts of Australian women, to determine the extent to which the dietary patterns differ between the cohorts and to assess whether they vary according to socio-demographic and behavioural characteristics and patterns of nutrient intake.

Study

The Australian Longitudinal Study on Women’s Health (ALSWH) began in 1996 and is a national longitudinal study of factors affecting the health and well-being of women. Participants of ALSWH provided information on dietary intake by completing an 80-item food frequency questionnaire for women aged 50-55 years (n=10150; “mid-age”) in 2001 and aged 25-30 years (n=7371; “young”) in 2003.

Method

Factor analysis (FA) was used to identify dietary patterns and a pattern score was calculated from the consumption of the food items identified with each dietary pattern. Initially FA was conducted separately for young and mid-age women and since the dietary patterns identified were similar, data from the two cohorts were combined. A higher pattern score is associated with more frequent consumption of items that makes up that dietary pattern.

Results

Six dietary patterns were identified among the women. Patterns identified were labelled “cooked vegetables”, “fruit”, “Mediterranean-style”, “processed meat, meat and takeaway”, “reduced fat dairy” and “high fat and sugar foods”.

Age effect

The mid-age cohort had higher scores on the cooked vegetables, fruit, Mediterranean-style, reduced fat dairy, and high fat and sugar foods patterns and lower scores on the processed meat, meat and takeaway pattern than the younger women.

Demographic factors

Living in rural and regional areas was associated with higher dietary pattern scores for the cooked vegetables, processed meat, meat and takeaway and high fat and sugar foods patterns and lower scores on the fruit and Mediterranean-style patterns. Not being married was associated with higher scores on the fruit pattern and lower scores on the cooked vegetables, and processed meat, meat and takeaway patterns.

Socio-economic factors

Higher education levels were associated with lower scores on the cooked vegetables and processed meat, meat and takeaway patterns, and higher scores on the fruit, Mediterranean-style, reduced fat dairy and high fat and sugar foods patterns. Being unemployed was associated with higher scores on the cooked vegetables and processed meat, meat and takeaway, and high fat and sugar foods patterns, and with lower scores on the Mediterranean-style pattern than managers or professionals.

Health behaviours

Higher physical activity levels were associated with higher scores on the cooked vegetables, fruit, Mediterranean-style, and reduced fat dairy patterns and lower scores on the processed meat, meat and takeaway pattern. Compared to healthy weight participants, overweight and obese participants had higher scores on the cooked vegetables, processed meat, meat and takeaway, and reduced fat dairy patterns and lower scores on the Mediterranean-style and high fat and sugar foods patterns. Smoking was associated with higher scores on the processed meat, meat and takeaway and lower scores on the reduced fat dairy, high fat and sugar foods and fruit (moderate to heavy smokers only) patterns. Participants classified as having risky alcohol drinking behaviours had higher scores on the Mediterranean-style and processed meat, meat and takeaway patterns and lower scores on the cooked vegetables, fruit, reduced fat dairy (high risk drinker only), and high fat and sugar food patterns than the low risk drinkers.

Conclusions

Healthier dietary patterns were associated with other favourable health related behaviours, higher socio-economic status, and living in urban areas. In spite of differences in the level of consumption of individual food items, the similarity in dietary patterns across two generations of women suggests that policies and interventions to improve diet should focus on social and economic factors and general health-related behaviours rather than different age groups.