A total of 10,685 papers were searched from three databases after removing duplicates. Studies identified were screened based on titles and abstracts, and finally full texts of 375 papers including the 54 papers which were identified from the reference lists were assessed according to the inclusion and exclusion criteria. Ultimately, 47 papers were included in the present study. Full details of the search are outlined in Fig. 1.

Full characteristics of the papers and CASP scores from quality assessment are shown in Table 1. Within the included papers, 24 papers reported findings on total dairy consumption. 16 papers investigated milk only. The remaining 7 papers investigated sub-groups of dairy products. Dairy intake data from 21 papers were draw from several national surveys conducted in China [46, 47, 54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72]. Within papers that reported the number of participants, sample sizes ranged from 117 to over 90,000. With respect to reported dietary intake assessment methodology, 24-hour dietary recalls [46, 47, 54,55,56,57,58,59,60,61,62,63,64,65, 67,68,69,70, 73,74,75,76], Food Frequency Questionnaires [71, 72, 77,78,79,80,81,82,83,84,85,86,87,88], Questionnaires or in-person interview [38, 45, 72, 89,90,91,92], and Internet-based dietary questionnaire for Chinese (IDQC) [93,94,95] were used in the data collection in reported studies to assess overall diet.

Of the 47 studies included in the final review, 12 reported dairy consumption across different age groups [45,46,47, 55, 62,63,64,65, 69, 73, 79, 89] (Table 2). In three studies, dairy consumption in those aged or average age over 60 were compared with other age cohorts [45, 46, 73]. Four studies focused on older cohorts aged over 50, with one reporting the differences in dairy intakes in those aged 50–70 [79], one that compared individuals aged 60–79 and 80 over [62], and three that compared ages 60–69 and 70 over [55, 65, 69]. One didn’t compare intakes between age groups but reported and compare the median age at low, high and non-consumer groups [64]. The other remaining studies included dairy consumption of working-age adults (20–59 years) [47], (18–59 years) [63], while one study used just 3 age groups to cover all ages (< 30, 30–50 and > 50) [89].

Of the three studies that compared dairy consumption in population groups aged under and over 60 years, two of these studies showed that people aged over 60 years reported consuming higher amounts [45], while had lower frequency of milk intake [46], compared to other age groups. Ba et al. [73] found that older adults had higher intakes of milk than younger adults with daily intakes reported in older adults (≥ 60 years) of 163.4 g/d, which was significantly greater than intakes reported in those aged 18–44 years and 45–59 years, with reported milk intakes of 75.8 and 96.6 g/d, respectively.

Focusing on people aged over 50 years, dairy consumption was reported in four studies. Xu et al. [55] reported that the median dairy intakes in males aged 60–69 years who consumed dairy in 2009 was 200 g/d, while the number in males aged 70 years and over was only 162 g/d. Likewise, Zong et al. [79] found that, within the age group 50–70 years, participants with higher intakes of dairy products were more likely to be of a younger age. In addition, Liu et al. [69] and Wang et al. [65] both found that people aged 70 years and over had significantly higher dairy intakes than those aged 60–69 years (P < 0.001 and P < 0.05 separately), with average intakes in these two age groups of 39.57 and 28.49 g/d, respectively. Similarly, Huang et al. [62] compared differences in dairy consumption between the age groups 60–79 years and 80 years and over, reporting that people aged over 80 years consumed significantly more dairy. One of the largest studies, Tian et al. [47] assessed dietary intake in residents from 12 cities and provinces in 2004, 2006, 2009 and 2011, and analysed intakes across two age groups (20–39 years, 40–59 years). Within this study, those aged 40–59 years reported higher mean daily dairy intakes than those aged 20–39 years, with intakes of 14.2 ± 55.8 g/d and 13.0 ± 47.1 g/d in each age group, respectively. However, this difference was not significant (P > 0.05). Similarly, results from the survey of Bai et al. [89], conducted in Qingdao city in 2005, showed that the people aged over 50 years consumed more milk than other age groups. However, these differences were not statistically tested, and only reported descriptively. Additionally, Wang et al. [63] analysed the national dairy consumption data from 1989 to 2011, finding that dairy consumers aged 40–59 years had higher average dairy intakes than adults aged 18–39 years in most of the years except in 1989, 1997 and 2011. Although, this difference was not significant (P > 0.05).

Of the 13 studies reporting on dairy consumption across location-specific cohorts comparing people living in different cities or provinces, two papers focused on dairy consumption in individual cities [38, 45], and eleven papers reported on dairy consumption in different regions of China classified by urban, rural; North, South, costal, inland; East, West, central; the size of city or economic status of rural area [46, 47, 56, 63,64,65, 67, 68, 71, 72,