The Association Among Social Support, Self-Efficacy, Use of Mobile Apps, and Physical Activity: Structural Equation Models With Mediating Effects.

BACKGROUND: Physical inactivity is a risk factor for chronic noncommunicable diseases. Insufficient physical activity has become an important public health problem worldwide. As mobile apps have rapidly developed, physical activity apps have the potential to improve the level of physical activity among populations. OBJECTIVE: This study aimed to evaluate the effect of physical activity apps on levels of physical activity among college students. METHODS: A Web-based questionnaire was used to survey college students in Beijing from December 27, 2017, to January 5, 2018. According to a previous survey, 43% of college students using physical activity apps and 36% of those who never used such apps achieved the physical activity recommendations. In this study, the sample size was calculated to be 500. The questionnaire consisted of 5 parts: the use of physical activity apps, sports habits, social support, self-efficacy, and social demographic information. Structural equation modeling was used to test the relationships between the use of physical activity apps, self-efficacy, social support, and level of physical activity. RESULTS: Of the 1245 participants, 384 college students (30.8%) used physical activity apps (in the past month). Of these 384 students, 191 (49.7%) gained new friends via the app. College students who were using physical activity apps had a higher level of physical activity and higher scores for social support and self-efficacy (P<.001) than those who did not use such apps. The use of physical activity apps significantly affected the mediating effect of physical activity level through social support (beta=.126; P<.001) and self-efficacy (beta=.294; P<.001). Gender played an important role in app use, self-efficacy, and physical activity in the mediation model: male users spent more time on physical activity and had higher self-efficacy scores (P<.001). CONCLUSIONS: This study focused on college students in Beijing and found that the use of physical activity apps is associated with higher physical activity levels among these students. This effect is mainly through the mediation effect of social support and self-efficacy, rather than the direct effect of physical activity apps. The use of physical activity apps is associated with a higher social support level and higher self-efficacy score. Furthermore, a high social support level and high self-efficacy score are associated with higher physical activity levels.

Examination of selected national policies towards mandatory folic acid fortification.

The purpose of this paper is to present an examination of the contrasting policies towards mandatory folic acid fortification in six countries from different regions of the world. Three questions are addressed: 1) What is the policy of the country? 2) Why was the policy adopted? 3) What lessons have been learned? Policy contrasts among countries were assessed as reflecting different interpretations of the potential risks and benefits associated with folic acid fortification. Although commonalities were identified, it was considered unlikely that there could be a standard policy response for all countries. Instead, a country-by-country policy response based on national circumstances is indicated.

[Effect of the whey basic protein on bone mineral density].

OBJECTIVE: To examine the effects of the whey basic protein on bone metabolism of Sprague-Dawley (SD) rats and healthy mid-aged women. METHODS: Forty-four female SD rats were randomized by weight into four groups of eleven rats each and fed 10 mg x kg BW(-1) x d(-1), 20 mg x kg BW(-1) x d(-1), 30 mg x kg BW(-1) x d(-1) of whey basic protein and control diet was given respectively by intragastrically injection for 90 days. Bone mineral density of femur was measured by dual-energy X-ray absorptiometry in vitro. Sixty-three health women [(37.9 +/- 4.3) years old] were randomly assigned to treatment with placebo, 30 mg whey basic protein per day or 60 mg whey basic protein per day for 24 weeks. The bone mineral density (BMD) of the lumbar vertebrae L2-LA, femoral neck and right calcaneus of each subject were measured by dual-energy X-ray absorptiometry (DXA) at 0 and the 24th week of treatment. Serum bone specific alkaline phosphatase and N-telopeptide (NTX) were measured at 0 and the 14th week. RESULTS: The mean BMD value of the distal end of the femur in 10 mg x kg BW(-1) x d(-1) whey basic protein group was significantly higher than that of the control group at the end of the trail. But after treatment by doses of whey basic protein used in the study, there were no differences between the control group and others groups on bone mineral density in the human trail. CONCLUSION: Whey basic protein should enhance the bone mineral density of the rats' femur and no obvious effect was detected in the human trail.

[Effect of milk basic protein on rat bone mineral density].

OBJECTIVE: To investigate the effect of milk basic protein (MBP)'s on bone mineral density (BMD) and hemobiochemical indexes in normal and ovariectomized (ovx) rats. METHODS: 48 female Sprague-Dawley rats were ovariectomized and another 12 rats received a sham operation (sham). The ovx rats were randomly separated into 4 groups: ovx control, ovx low-does, ovx media dose, and ovx high-dose while 44 normal SD female rats into 4 groups: normal control, normal low-dose, normal media-dose, and normal high-dose. MBP at 10, 20 and 30 mg/(kg x d) were applied in rat diet for continuous 90 days. BMD (at proximal, middle of diaphysis, and distal end) and bone mineral content (BMC) was measured by dual energy X-ray absorptiomery. In addition, serum total protein (TP), total cholesterol (CHO), glucose (GLU) were determined. RESULTS: The bone density and mineral composition at distant end of femur in low-dosage BMP group were significantly higher than those in normal control group, while no significant change of bone density was observed with MBP treatment in ovx groups. Total serum protein level and albumin level were significantly higher in MBP treatment groups than those in normal control group. CONCLUSION: MBP at 10 mg/kg bw significantly elevated femoral distant-end bone density, as well as the total blood protein level and albumin level in normal rat. However, similar effect was not observed in ovx rat.