Lifetime squatting, lotus (cross leg sitting) and side-knee bending positions increase the risk of knee osteoarthritis. Other authors have shown that repetitive joint loading tasks (eg. kneeling, squatting, stair climbing) are a high risk factor for developing knee osteoarthritis.

-Clin Orthop 2007 Jan; 454:147-54

Until now there is no scientific reason or theory which explains why females are at increased risk for knee osteoarthritis. But, there is one scientific article which has shown that joint cartilage is substantially less in females compared to the males, and so the females have relatively little cartilage to start with, which probably puts them under greater risk for getting arthritis.

-Arthritis & Rheumatism Vol. 43, No. 11, Nov 2000, 2543–49

Ex-elite table tennis players were found to have increased levels of radiological signs of osteoarthritis in the knee joint though this did not transpire through to altered levels of physical disability or knee stiffness in these players when compared with subjects from the general population. For sports and recreational activity, the OASIS group states with a high degree of scientific evidence, that these activities are a risk factor for knee and hip OA and that the risk correlates with intensity and duration of exposure.

Ref: Joint Bone Spine 2006 Jul; 73(4):442-55; BMC Musculoskeletal Disorders 2012, 13:12

People believe that arthritis is because of poor diet, especially low calcium. But what we should understand is that arthritis is because of wear and tear of the cartilage, which is normally devoid of calcium. Hence calcium levels have no influence on joint arthritis. Whereas bone needs calcium for maintaining its normal strength and whenever calcium is deficient in food the result is weak bones otherwise called as osteoporosis.

Researchers have shown that among older adults, planus foot morphology is associated with a moderately increased prevalence of frequent knee pain and medial tibiofemoral cartilage damage. There is a possible role of supportive shoes, corrective arch supports, and compensatory foot orthoses the prevention and/or treatment of knee disorders among flat-footed older adults.

Results suggest that a 10% weight loss in an overweight and obese osteoarthritic population elicits positive changes in the mechanical pathway to knee osteoarthritis by having lower knee joint compressive loads during walking compared to low and no weight loss groups. The difference in compressive forces was due, in large part, to reductions in hamstring cocontraction during the stance phase of walking.

Osteoarthritis Cartilage. Author manuscript; PMC 2012 September 18

Glucosamine is a basic component of the knee cartilage and has long been used as a treatment option for osteoarthritis of the knee joint. Glucosamine is safe and is well tolerated for at least 3 years and the early concerns about its negative impact on glucose control do not appear to be justified by later research.

Australian Family Physician Vol. 39, No. 9, september 2010

Limb alignment (the wider pelvis, increased thigh bone anteversion, & knock knees) with decreased hamstrings support is a possible cause for the increased ACL injury rates in women. Further studies have documented that women have a smaller notch (space for ACL) than men & it has been reported that athletes who sustain ACL injuries have a narrow notch. Also studies show that cyclic variation of estrogen may affect the ligament metabolism & make females more prone to injury during the estrogen phase of their cycle.

Knee Surg Sports Traumatol Arthrosc 1999;7:209–214; Clin Orthop 2001;383:268–281