Table 2: Measures and time-frame for the study Intervention timeline – year Measures Dietary Intake Sedentary behaviour Physical activity Family Food Environment Family physical activity & Sedentary Environment Demographic Data Anthropometric Data Parent Child Parent Child Parent Child Parent Parent Parent Parent Child 1 2 3 3 months 6 months 9 months 15 months 18 months Infant Age 12 months BMC Public Health 2008, 8:103 http://www.biomedcentral.com/1471-2458/8/103 Dietary intake Dietary intake for mother and father will be assessed using The Cancer Council's Dietary Questionnaire for Epidemi- ological Studies (Version 3) at baseline and study conclu- sion. This questionnaire is an updated version of the semi- quantitative food frequency questionnaire specifically developed for the Melbourne Collaborative Cohort Study [49]. Child's dietary intake will be assessed by telephone- administered multi-pass 24-hour recall with parents [50]. Visual aids will be provided to primary carers in advance of interviews to help in the estimation of quantities of food consumed. Three days of dietary data will be col- lected (including one weekend day) when the infant is 9 and 18 months of age. Physical activity Parents will report their frequency and duration in physi- cal activity during the previous week using the Active Aus- tralia Survey [51]. In addition, at 12 and 18 months parents will be asked to report the number of hours their child typically spends playing outdoors on weekdays and weekend days. Sedentary behaviors Parents will be asked the amount of time the infant spends watching television on a typical weekday and on a typical weekend day [52], and to estimate the amount of time each day that the child spends immobile. Parents will also report the total time they spend watching televi- sion during their leisure-time in a typical week [53]. Home food environment Three aspects of the home food environment will be assessed. Aspects of nutrition knowledge focused around nutrition targets of the intervention will be assessed mod- ified subscales of the validated Nutrition Knowledge Questionnaire [54], Parent Feeding Style will be assess using the Child Feeding Questionnaire (CFQ) [55], the Caregivers Feeding Style Questionnaire CFSQ [56]. Family physical activity and sedentary environment Parents will be asked general questions relating to their knowledge about physical activity in early childhood, their interactions with their child around physical activity and an audit checklist on the physical activity and seden- tary home environment. Standard demographic and socio-economic information will be collected by parental report. Anthropometric measures (height/length and weight) on the infant and parents will be collected by trained staff. Data analysis All analyses will be conducted using the intention to treat principle. Generalized Estimating Equations (GEE) [57] will be used to fit regression models to describe the effects of the intervention on key outcome variables among par- ents and infants. Separate models will be fitted, to deter- mine differences in key outcome variables in the intervention and control groups. Discussion The prevalence of obesity in early childhood is rapidly increasing and is determined, in part, by eating, physical activity and sedentary behaviours. These behaviors are predominantly learnt at home in the first five years of life, and impact upon health throughout life. Given this, the early years hold promise as a time when obesity preven- tion may be most effective. However, research in this early period of life is lacking. This cluster-randomized trial will be one of the first to investigate whether a health promo- tion program delivered to first-time parents in their usual social settings can promote healthy eating, physical activ- ity and reduced sedentary behaviours in infants. If effec- Page 7 of 9 (page number not for citation purposes)