SCIENTIFIC ARTICLE Australian Dental Journal 2011; 56: 33–39 doi: 10.1111/j.1834-7819.2010.01280.x Risk indicators for early childhood caries in 2-year-old children in southern China Y Zhou,* HC Lin,* ECM Lo, MCM Wong  *Department of Preventive Dentistry, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China.  Faculty of Dentistry, The University of Hong Kong, Hong Kong. ABSTRACT Background: The aim of this study was to explore the relationship between early childhood caries (ECC) and relevant socio-economic, behavioural and biological experiences in the life course of children. Methods: A cross-sectional study of 2-year-old children was analysed. A questionnaire collected socio-economic and behavioural data during the first two years of the participants’ life. Caries experience was recorded at the level of cavitation and oral hygiene was assessed using the Visible Plaque Index (VPI). Microbiological investigation collected information on colony-forming units (CFU) of Streptococcus mutans (S. mutans). The outcome was ECC. Bivariate and multiple logistic regression analyses were performed. Results: The study included 394 children, with 109 having ECC and 285 being caries-free. The mean decayed, missing and filled primary teeth (dmft) score of the ECC group was 3.65 ± 3.12, with decayed teeth making up 100% of the score. The results of the final logistic regression analysis showed that ECC was significantly associated with the mother’s schooling at child’s birth [<12 years vs. ‡12 years, OR = 1.80], VPI score [>60% vs. 0–20%, OR = 5.71], and S. mutans [‡10 5 CFU ⁄ ml vs. 0 CFU ⁄ ml, OR = 3.80]. Conclusions: Social, behavioural and biological factors during the life course of 2-year-old children in southern China are associated with the development of ECC. Keywords: Caries, life course, risk factor. Abbreviations and acronyms: CFU = colony-forming units; dmft = mean decayed, missing and filled primary teeth; ECC = early childhood caries; OR = odds ratios; VPI = Visible Plaque Index. (Accepted for publication 11 April 2010.) INTRODUCTION The oral health of preschool children has improved in most industrialized countries over the past few decades. However, dental caries remains an important childhood disease affecting a considerable proportion of young children in China. The Third National Oral Health Survey in China showed that the prevalence of early childhood caries (ECC) was 66% and the mean dmft score was 3.5 in the 5-year old age group. 1 It was also found that 3–6 year old children in southern China had a higher mean dmft score than the national average. 2,3 ECC develops early in life. It is important to establish the relationship between the children’s social, behavio- ural and biological factors in early life and ECC so that effective measures can be implemented at appropriate times to prevent ECC. Although the risk factors for ECC have been reported in a number of studies, 4 these have mostly been conducted in Western industrialized countries. The status and risk factors associated with ECC in Chinese children, particularly those under 3 years, are not yet clear. Therefore, research into the associated risk factors for ECC in young Chinese children is required. The life course approach offers an alternative way of linking early life factors to later disease. One of the basic tenets is that, throughout life, adverse exposures gradually accumulate by way of ill-health episodes, environmental factors or individual behaviours which increase the person’s risk of chronic disease and mortality. 5 Thus, the life course approach seems to be useful in elucidating when and how risk factors occur to identify the most appropriate time for preventive interventions. Dental caries is a chronic, cumulative, moderately prevalent oral disease that shares similar risk factors ª 2010 Australian Dental Association 33 Australian Dental Journal The official journal of the Australian Dental Association